Protection from the Evil Eye: How?
Question

What is the evil eye? I've seen this terminology being used so many times on this webpage. Can you please explain in detail?
Praise be to Allah.What is the evil eye?
Here follows some information and fatwas (rulings) that have to do with the evil eye. We ask Allah to benefit readers thereby. 
The scholars of the Standing Committee were asked: 
What is the definition of the evil eye? Allah says (interpretation of the meaning): 
“And from the evil of the envier when he envies.” [Al-Falaq 113:5] 
Is the hadith (narration) of the Prophet (peace and blessings of Allah be upon him) sahih (authentic) in which it says that “One third of those who are in the grave are there because of the evil eye”? If a person thinks that someone is envying him , what should the Muslim do and say? If the person who put the evil eye on someone washes himself, will the water he used bring healing to his victim? And should he drink the water or wash himself with it? 
They replied: 
The Arabic word al-‘ayn (translated as the evil eye) refers to when a person harms another with his eye. It starts when the person likes a thing, then his evil feelings affect it, by means of his repeated looking at the object of his jealousy. Allah commanded His Prophet, Muhammad (peace and blessings of Allah be upon him), to seek refuge with Him from the envier, as He said (interpretation of the meaning): 
“And from the evil of the envier when he envies.” [Al-Falaq 113:5] 
Everyone who puts the evil eye on another is envious, but not every envier puts the evil eye on another. The word hasid (envier) is more general in meaning than the word ‘aain (one who puts the evil eye on another), so seeking refuge with Allah from the one who envies includes seeking refuge with Him from the one who puts the evil eye on another. The evil eye is like an arrow which comes from the soul of the one who envies and the one who puts the evil eye on another towards the one who is envied and on whom the evil eye is put; sometimes it hits him and sometimes it misses. If the target is exposed and unprotected, it may affect him, but if the target is cautious and armed, the arrow will have no effect and may even come back on the one who launched it. Adapted from Zad al-Ma'ad. 
There are ahadith (reports) from the Prophet (peace and blessings of Allah be upon him) which speak of the effects of the evil eye. For example it is narrated in al-Sahihayn that ‘Aishah (may Allah be pleased with her) said: The Messenger of Allah (peace and blessings of Allah be upon him) used to tell me to recite ruqyah (incantation) for protection against the evil eye.  
Muslim, Ahmad and al-Tirmidhi narrated from Ibn ‘Abbas (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: “The evil eye is real and if anything were to overtake the divine decree, it would be the evil eye. When you are asked to take a bath (to provide a cure) from the influence of the evil eye, you should take a bath.”
Imam Ahmad and al-Tirmidhi narrated that Asma bint ‘Umays said: “O Messenger of Allah, the children of J’afar have been afflicted by the evil eye, shall we recite ruqyah for them?” He said, “Yes, for if anything were to overtake the divine decree it would be the evil eye.”
Abu Dawud narrated that ‘Aishah (may Allah be pleased with her) said: The person who had put the evil eye on another would be ordered to do wudu, then the person who had been afflicted would wash himself (with that water).
Imam Ahmad, Malik, al-Nasai and Ibn Hibban narrated from Sahl ibn Hanif that the Prophet (peace and blessings of Allah be upon him) came out and traveled with him towards Makkah, until they were in the mountain pass of al-Kharar in al-Jahfah. There Sahl ibn Hanif did ghusl (bathed), and he was a handsome white-skinned man with beautiful skin. ‘Amir ibn Rabi'ah, one of Banu ‘Adiyy ibn Ka'b looked at him whilst he was doing ghusl and said: “I have never seen such beautiful skin as this, not even the skin of a virgin,” and Sahl fell to the ground. They went to the Messenger of Allah (peace and blessings of Allah be upon him) and said, “O Messenger of Allah, can you do anything for Sahl, because by Allah he cannot raise his head.” He said, “Do you accuse anyone with regard to him?” They said, “‘Amir ibn Rabi'ah looked at him.” So the Messenger of Allah (peace and blessings of Allah be upon him) called ‘Amir and rebuked him strongly. He said, “Why would one of you kill his brother? If you see something that you like, then pray for blessing for him.” Then he said to him, “Wash yourself for him.” So he washed his face, hands, forearms, knees and the sides of his feet, and inside his izar (lower garment) in the vessel. Then that water was poured over him, and a man poured it over his head and back from behind. He did that to him, then Sahl got up and joined the people and there was nothing wrong with him.  Classed as sahih (authentic) by al-Albani in al-Mishkat.
The majority of scholars are of the view that people can indeed be afflicted by the evil eye , because of the ahadith (reports) quoted above and others, and because of the corroborating reports and other evidence. 
With regard to the hadith that you mention, “One third of those who are in the grave are there because of the evil eye,” we do not know how sound it is, but the author of Nayl al-Awtar said that al-Bazzar narrated with a hasan isnad (sound chain of narrators) from Jabir (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: “Most of those who die among my ummah (followers) die because of the will and decree of Allah, and then because of the evil eye.” 
The Muslim has to protect himself against the devils among the evil jinn and mankind, by having strong faith in Allah and by putting his trust in Him and seeking refuge with Him and beseeching Him, reciting the prayers for protection narrated from the Prophet (peace and blessings of Allah be upon him), reciting al-Mu’awwadhatayn [the last two surahs of the Quran], Surat al-Ikhlas, Surat al-Fatihah, and ayat al-Kursi. 
Du`a  for protection from evil eye
Du’as for protection include the following: 
A’udhu bi kalimat-illah il-tammati min sharri ma khalaq (I seek refuge in the perfect words of Allah from the evil of that which He has created). 
A’udhu bi kalimat-illah il-tammati min ghadabihi wa ‘iqabihi, wa min sharri ‘ibadihi wa min hamazat al-shayatini wa an yahduroon (I seek refuge in the perfect words of Allah from His wrath and punishment, from the evil of His slaves and from the evil promptings of the devils and from their presence). 
And one may recite the words of Allah: 
“Hasbi Allahu la ilaha illa huwa, ‘alayhi tawakkaltu wa huwa Rabbul-'arsh il-‘azim
 
(Allah is sufficient for me. La ilaha illa Huwa (none has the right to be worshipped but He) in Him I put my trust and He is the Lord of the Mighty Throne).”
[9:129 – interpretation of the meaning] 
And there are other similar du’as that are prescribed in shari’ah (Islamic law). This is what was meant by Ibn al-Qayyim in the words quoted at the beginning of this answer. 
If it is known or suspected that a person has been afflicted by the evil eye , then the one who put the evil eye on him should be ordered to wash himself for his brother. So a vessel of water should be brought, and he should put his hand in it and rinse out his mouth into the vessel. Then he should wash his face in the vessel, then put his left hand into the vessel and wash his right knee, then put his right hand in the vessel and wash his left knee. Then he should wash inside his garment. Then the water should be poured over the head of the one on whom he put the evil eye, pouring it from behind in one go. Then he will be healed, by Allah’s leave.” (Fatawa al-Lajnah al-Daimah li’l-Buhuth al-‘Ilmiyyah wa’l-Ifta)
Can the evil eye afflict a person? 
Shaykh Muhammad al-Salih al-‘Uthaymin was asked: 
Can the evil eye afflict a person? How is it treated? Does being on one's guard against it contradict putting one's trust in Allah? 
He replied: 
Our opinion concerning the evil eye is that it is real and is proven both by Islamic teachings and by real life experiences. Allah says (interpretation of the meaning): 
“And verily, those who disbelieve would almost make you slip with their eyes (through hatred).” [Al-Qalam 68:51] 
Ibn ‘Abbas (may Allah be pleased with him) and others said, commenting on this verse: this means, they put the evil eye on you with their glances. The Prophet (peace and blessings of Allah be upon him) said: “The evil eye is real and if anything were to overtake the divine decree, it would be the evil eye. When you are asked to take a bath (to provide a cure) from the influence of the evil eye, you should take a bath.” (Muslim). Al-Nasai and Ibn Majah narrated that ‘Amir ibn Rabi'ah passed by Sahl ibn Hanif when he was bathing … and he quoted the hadith. 
Reality confirms this and it cannot be denied. 
How to protect yourself from the evil eye
In the event that you are afflicted by the evil eye, you should use the treatments recommended in the Shari’ah, which are: 
1 – Reciting ruqyah. The Prophet (peace and blessings of Allah be upon him) said, “There is no ruqyah except in the case of the evil eye or fever.” al-Tirmidhi, Abu Dawud. Jibril (peace be upon him) used to do ruqyah for the Prophet (peace and blessings of Allah be upon him) and say, “Bismillahi arqika min kulli shayin yudheeka, min sharri kulli nafsin aw ‘aynin hasid Allahu yashfeek, bismillahi arqeek (In the name of Allah I perform ruqyah for you, from everything that is harming you, from the evil of every soul or envious eye may Allah heal you, in the name of Allah I perform ruqyah for you).” 
2 – Asking the person who has put the evil eye on another to wash, as the Prophet (peace and blessings of Allah be upon him) commanded ‘Amir ibn Rabi'ah to do in the hadith quoted above. Then the water should be poured over the one who has been afflicted.  
With regard to taking his waste, such as his urine and stool, there is no basis for doing so; the same applies to taking any of his belongings. Rather what is narrated is that which is mentioned above, washing his limbs and washing inside his garment, or likewise washing inside his headgear and garments. And Allah knows best. 
Does taking precautions against the evil eye contradict tawakkul?
There is nothing wrong with taking precautions against the evil eye before it happens, and this does not contradict the idea of tawakkul (putting one's trust in Allah). In fact this is tawakkul, because tawakkul means putting one’s trust in Allah whilst also implementing the means that have been permitted or enjoined. The Prophet (peace and blessings of Allah be upon him) used to seek refuge for al-Hasan and al-Husayn and say: U’idhukuma bi kalimat Allah al-tammati min kulli shaytanin wa hammah wa min kulli ‘aynin lammah (I seek refuge for you both in the perfect words of Allah, from every devil and every poisonous reptile, and from every evil eye).’”  Al-Tirmidhi, Abu Dawud. And he would say, “Thus Ibrahim used to seek refuge with Allah for Ishaq and Ismail, peace be upon them both.” [al-Bukhari]. (Fatawa al-Shaykh Ibn ‘Uthaymin)
Please see also the answers to questions no. 7190 and 11359 . 
And Allah knows best.