Assalaamu alaykum. I heard Prophet Adam, peace be upon him, was titled Ab Al-Bashar. Is that authentic? Why is he known as Abul Bashar?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

Aadam (Adam) is the origin of man's creation. Allah says (what means): {O mankind, fear your Lord, Who created you from one soul and created from it its mate and dispersed from both of them many men and women. And fear Allah, through whom you ask one another, and the wombs. Indeed Allah is ever, over you, an Observer.} [Quran 4:1]

The one soul mentioned in the verse is Aadam as stated by the scholars of Tafseer (Quranic exegesis). It is for this reason that he is called Abu Al-Bashar (i.e. the father of mankind).

Also, he is described as such in the Sunnah of the Prophet . Abu Hurayrah narrated that the Prophet said in the long hadeeth about Shafaa‘ah (Intercession on the Day of Judgment), "…they would say: O Adam, you are Abu Al-Bashar..."

Allah knows best.