Why Must We Love the Prophet Muhammad?
Question

Why do we have to love, obey, follow and venerate our Prophet Muhammad (peace and blessings of Allah be upon him) the most (or more than any other person)?
Praise be to Allah.Muslims love Prophet Muhammad (peace and blessings of Allah be upon him) the most for the following reasons:

Allah has commanded us to obey the Prophet (peace and blessings of Allah be upon him). Allah says (interpretation of the meaning): 

“And obey Allah and the Messenger (Muhammad), and beware (of evil) and fear Allah. Then if you turn away, you should know that it is Our Messenger’s duty to convey (the Message) in the clearest way.” [Al-Ma'idah 5:92]

Allah has told us that obedience to the Prophet (peace and blessings of Allah be upon him) is obedience to Allah. Allah says (interpretation of the meaning): 

“He who obeys the Messenger (Muhammad), has indeed obeyed Allah, but he who turns away, then we have not sent you (O Muhammad) as a watcher over them.” [An-Nisa’ 4:80] 

Allah has warned us against failing to obey him, and that this may lead a Muslim into a trial that is the trial of Shirk (associating partners with Allah). Allah says (interpretation of the meaning): 
“Do not make [your] calling of the Messenger among yourselves as the call of one of you to another. Already Allāh knows those of you who slip away, concealed by others. So let those who dissent from his [i.e., the Prophet's] order [way or sunnah] beware , lest fitnah [trials or affliction] strike them or a painful punishment..” [An-Nur 24:63]   

Allah has told us that the status of Prophethood which He gave to His Prophet (peace and blessings of Allah be upon him) requires the believers to respect and venerate the Prophet (peace and blessings of Allah be upon him). Allah says (interpretation of the meaning): 
“Verily, We have sent you (O Muhammad) as a witness, as a bearer of glad tidings, and as a warner. In order that you (O mankind) may believe in Allah and His Messenger, and that you assist and honour him, and (that you) glorify (Allah’s) praises morning and afternoon.” [Al-Fath 48:8-9] 

The Muslim’s faith cannot be complete unless he loves the Prophet (peace and blessings of Allah be upon him), and until the Prophet (peace and blessings of Allah be upon him) is dearer to him than his father, his son, his own self and all the people. It was narrated that Anas (may Allah be pleased with him) said: The Prophet (peace and blessings of Allah be upon him) said: “No one of you will truly believe until I am dearer to him than his father, his son, his own self and all the people.” (Narrated by Al-Bukhari, 15; Muslim, 44). 

`Abdullah ibn Hisham (may Allah be pleased with him) said: “We were with the Prophet (peace and blessings of Allah be upon him) when he was holding the hand of `Umar ibn Al-Khattab. `Umar (may Allah be pleased with him) said to him: “O Messenger of Allah, you are dearer to me than everything except my own self.” The Prophet (peace and blessings of Allah be upon him) said: “No, by the One in Whose hand is my soul, (you will not have complete faith) not until I am dearer to you than your own self.” `Umar said to him: “Now, by Allah, you are dearer to me than my own self.” The Prophet (peace and blessings of Allah be upon him) said: “Now (you are a true believer), O `Umar.” (Narrated by Al-Bukhari, 6257) 
Shaykh Al-Islam Ibn Taymiyyah (may Allah have mercy on him) said: 
“The reason why it is obligatory to love the Prophet (peace and blessings of Allah be upon him) and venerate him more than any other person is that we cannot attain what is good in this world and in the Hereafter except through the Prophet (peace and blessings of Allah be upon him), by believing in him and following him. That is because no one can be saved from the punishment of Allah, and the mercy of Allah cannot reach him except by means of the Prophet (peace and blessings of Allah be upon him), by believing in him, loving him, being loyal to him and following him. This is the means by which Allah will save him from punishment in this world and in the Hereafter. This is the means by which he will attain what is good in this world and in the Hereafter. The greatest blessing is the blessing of faith, which can only be attained through him, and which is more beneficial (to the person) than his own self and his wealth. He (peace and blessings of Allah be upon him) is the one by means of whom Allah brings people forth from darkness into light, and there is no other way to Allah. As for a person’s self and family, they will not avail him anything before Allah…” (Majmu’ Al-Fatawa, 27/246) 
One of the scholars said:
“If a person thinks of the benefits that he has been given through the Prophet (peace and blessings of Allah be upon him), through whom Allah brought him forth from the darkness of disbelief into the light of faith, he will realise that he is the cause of his soul will remain forever in eternal bliss, and he will understand that this benefit is greater than all others. So he (peace and blessings of Allah be upon him) deserves that his share of a person’s love should be greater than anyone else’s. However, people vary with regard to that, depending on the extent to which they bear that in mind or neglect it. Everyone who truly believes in the Prophet (peace and blessings of Allah be upon him) will inevitably have a strong love for him , but they differ in the extent and depth of their love for him. Some of them have a great deal of love for him and some have only a little, like those who are absorbed in their own whims and desires most of the time. But when mention of the Prophet (peace and blessings of Allah be upon him) is made, most of them long to see him, and prefer that over their own family, sons, wealth and fathers. But that feeling quickly fades because of other distractions. And Allah is the One Whose help we seek.”  (See Fath Al-Bari, 1/59) 
This is what is referred to in the verse where Allah says (interpretation of the meaning): 
“The Prophet is closer to the believers than their own selves.” [Al-Ahzab 33:6]
Ibn Kathir (may Allah have mercy on him) said: 
“[Allah] knew how compassionate His Messenger (peace and blessings of Allah be upon him) was towards his Ummah, and how sincere he was towards them, so He made him closer to them than their own selves, and decreed that his judgement among them should take precedence over their own preferences.” (Tafsir Ibn Kathir, 6/380) 
Shaykh Ibn Sa’di (may Allah have mercy on him) said: 
“Allah tells the believers something by which they may understand the position and status of the Messenger (peace and blessings of Allah be upon him), so that they might interact with him appropriately. So He said: “The Prophet is closer to the believers than their own selves”, the closest thing to a person and the most deserving of love is his own self. Yet, the Messenger is closer to him than his own self, because he (peace and blessings of Allah be upon him) was so kind and sincere and compassionate towards the believers. He was the kindest and most merciful of mankind. The Messenger of Allah (peace and blessings of Allah be upon him) did the greatest of favours to all of mankind. Not the slightest good came to them and not the slightest harm was warded off from them except through him. Hence if there is a conflict between what a person himself wants or what other people want, and what the Messenger wants, then what the Messenger wants must take precedence. What the Messenger (peace and blessings of Allah be upon him) says cannot be overridden by what any person says, no matter who he is. They should sacrifice their selves, their wealth and their children, and put love for him before their love for all others.” 
What the scholars have said may be summed up by noting that the wrath of Allah and the Fire of Hell are the things that we fear the most, and we cannot be saved from them except through the Messenger (peace and blessings of Allah be upon him). The pleasure of Allah and the garden of Paradise are the things that we want the most, but we cannot attain them except through the Messenger (peace and blessings of Allah be upon him). 
The Prophet (peace and blessings of Allah be upon him) referred to the former (i.e., being saved from Hell) when he said: “The likeness of me and you is that of a man who lit a fire and grasshoppers and moths started falling into it, and he tried to push them away. I am seizing your waistbands and trying to pull you away from the Fire but you are trying to get away from me.” (Muslim, 2285, from the Hadith of Jabir (may Allah be pleased with him); a similar Hadith was narrated by Al-Bukhari, 3427 from the Hadith of Abu Hurayrah (may Allah be pleased with him)). 
What is meant by this Hadith is that the Prophet (peace and blessings of Allah be upon him) likened the way in which the ignorant and disobedient rush to fall into the Fire of the Hereafter by means of their sins and following their whims and desires, and their keenness to fall into that Fire, even though he is trying hard to prevent them from doing so, to the way in which moths and other insects are fatally attracted to the fire. Both of them are keen to destroy themselves because of their ignorance of the consequences. (Sharh Muslim by An-Nawawi) 
The latter (i.e., entering Paradise) was referred to by the Prophet (peace and blessings of Allah be upon him) when he said: “All of my Ummah will enter Paradise except those who refuse.” They said: “O Messenger of Allah, who would refuse?” He said: “Whoever obeys me will enter Paradise and whoever disobeys me has refused.” (Al-Bukhari, 7280, from the Hadith of Abu Hurayrah (may Allah be pleased with him))