Who are the Muhajirin and Ansar?
Question

Can you tell us a little about the Ansar and Muhajirin, and their achievements, and the names of some of the Companions who belonged to each group (may Allah be pleased with them and make them pleased)?
Praise be to Allah.Firstly
The Muhajirin and Ansar are the Companions and students of the Messenger of Allah (blessings and peace of Allah be upon him). They are the best of this ummah and, indeed, the best of humanity after the Prophets and Messengers.
Their hearts were filled with love for Allah, may He be exalted, veneration of Him, fear of Him and faith in Him. They loved the Messenger (blessings and peace of Allah be upon him) more than they loved themselves, and they showed the greatest of sincerity in that. They offered their lives and their wealth and all that they possessed in support of this religion, and in defending it, spreading it and calling people to it.
There have never been and will never be any humans who are more perfect than them in faith and better than them in worship and in attitude and conduct.
They deserved the praise of Allah in many verses of the Holy Qur’an, and the praise of the Messenger (blessings and peace of Allah be upon him) in many hadiths.
In fact, the Prophet (blessings and peace of Allah be upon him) described loving them as part of faith, and he described hating them as part of hypocrisy, because the one who studies their biographies and learns about their faith and character, and the sacrifices they made in support of this religion cannot but love them, if he is a believer who loves this religion. If he hates them, then he is a hypocrite who hates this religion and hates to spread it and adhere to it.
Regarding the Muhajirin, they are the ones who became Muslim before the conquest of Makkah and migrated to join the Messenger (blessings and peace of Allah be upon him) in Madinah, where they settled. They left behind their homelands, their wealth and their families, seeking that which is with Allah, seeking to earn His good pleasure, and in support of this religion.
Regarding the Ansar, they are the people of Madinah who welcomed the Messenger (blessings and peace of Allah be upon him) and his Companions, the Muhajirin. They gave them refuge in Madinah and shared their wealth with them, not withholding anything from them out of stinginess, and they strove in Allah’s cause, offering their wealth and their lives.
One of the verses in which Allah praises the Muhajirin is:
{For the poor emigrants who were expelled from their homes and their properties, seeking bounty from Allah and [His] approval and supporting Allah and His Messenger, [there is also a share]. Those are the truthful} [al-Hashr 59:8].
This is testimony from Allah, may He be glorified and exalted, attesting to the purity of their hearts, and that they did not leave their homes and their properties for the sake of some worldly gain; rather they left seeking that which is with Allah, and in support of His religion, and they were sincere in their faith, their actions and their words.
Then Allah, may He be exalted, praises the Ansar, as He says:
{And [also for] those who were settled in al-Madinah and [adopted] the faith before them. They love those who emigrated to them and find not any want in their hearts of what the emigrants were given but give [them] preference over themselves, even though they are in privation. And whoever is protected from the stinginess of his soul - it is those who will be the successful} [al-Hashr 59:9].
In other words, those who lived in Madinah before the Muhajirin, and became Muslim before many of the Muhajirin. These Ansar sincerely loved the Messenger (blessings and peace of Allah be upon him) and his Companions, the Muhajirin: {They love those who emigrated to them} and did not envy the Muhajirin for what Allah, may He be glorified and exalted, had given them of virtue and honour [because the Muhajirin are more virtuous than the Ansar; hence the Messenger (blessings and peace of Allah be upon him) said: “Were it not for the Hijrah, I would have been one of the Ansar.” Narrated by al-Bukhari (4330)].
The Ansar were generous to the Muhajirin, giving them their wealth despite their own need for it: {but give [them] preference over themselves, even though they are in privation}. Then Allah, may He be exalted, testified that they would succeed, as a reward for them in return for these magnificent deeds.
And Allah, may He be exalted, says:
{And the first forerunners [in the faith] among the Muhajireen and the Ansar and those who followed them with good conduct - Allah is pleased with them and they are pleased with Him, and He has prepared for them gardens beneath which rivers flow, wherein they will abide forever. That is the great attainment} [at-Tawbah 9:100].
Here Allah, may He be exalted, tells us that He is pleased with the Muhajirin and Ansar, and He tells us that they will be among the people of Paradise, and that Paradise has been prepared for them.
In terms of the hadiths of the Messenger (blessings and peace of Allah be upon him), it is sufficient to note that he (blessings and peace of Allah be upon him) said: “The best of people are my generation, then those who come after them, then those who come after them.” Narrated by al-Bukhari (2652) and Muslim (2533).
The number of the Companions (may Allah be pleased with them) was over one hundred thousand, of whom we know several thousands, and the most famous of them are several hundred.
The best of them are: Abu Bakr as-Siddiq, then ‘Umar ibn al-Khattab, then ‘Uthman ibn ‘Affan, then ‘Ali ibn Abi Talib, then az-Zubayr ibn al-‘Awwam, Talhah ibn ‘Ubaydillah, ‘Abd ar-Rahman ibn ‘Awf, Sa‘d ibn Abi Waqqas, Abu ‘Ubaydah ibn al-Jarrah, and Sa‘id ibn Zayd (may Allah be pleased with them all). These are the ten who were given the glad tidings of Paradise, and all of them were Muhajirin.
With regard to the Ansar, the best of them include: Sa‘d ibn Mu‘adh, Sa‘d ibn ‘Ubadah, Ubayy ibn Ka‘b, Mu‘adh ibn Jabal, Usayd ibn Hudayr, al-Bara’ ibn Ma‘rur, As‘ad ibn Zurarah, Anas ibn an-Nadr, Anas ibn Malik, Hassan ibn Thabit, and ‘Abdullah ibn ‘Amr ibn Haram and his son Jabir ibn ‘Abdillah (may Allah be pleased with them all).
See also the answer to question no. 83121 for information on the virtue of the Companions (may Allah be pleased with them).
And Allah knows best.