Muadh ibn Jabal was a Sahabi of the Islamic prophet Muhammad. He was called by Muhammad "the one who will lead the scholars into Paradise."
He accepted Islam before the Second pledge at al-Aqabah and was one of those who took the pledge.
When Muhammad was sending Muadh to Yemen to teach the people about Islam, he personally bade farewell to him and walked for some distance alongside him as he set out to leave the city. It is said Muhammad informed Muadh that on his return to Medina, he will perhaps see only his Mosque and grave. Upon hearing this, Muadh began to cry.
When Muadh returned to Medina, the Khalifa (head of state) was Abu Bakr.
Al-Bayhaqi narrated in Shu`ab al-Iman (1:392 #512-513), and so did al-Tabarani, that Mu`adh ibn Jabal narrated that Muhammad said: "The People of Paradise will not regret except one thing alone: the hour that passed them by and in which they made no remembrance of Allah." Ali ibn Abu Bakr al-Haythami in Majma al-Zawa'id (10:74) said that its narrators are all trustworthy (thiqat), while Suyuti declared it hasan in his Jami` al-Saghir (#7701).
Ibn al-Jawzi recorded in Siffatu Safwah that Muadh bin Jabal advised his son, "My son! Pray the prayer of he who is just about to leave and imagine that you might not be able to pray ever again. Know that the believer dies between two good deeds; one that he performed and one that he intended to perform later on."
He accompanied Usama ibn Zaid on the Syrian expedition and died there in 18 AH due to plague.
The college for the study of Shariah law at Mosul University under the Islamic State is named after Mu`adh ibn Jabal.