He was regarded as the highest authority of the Qur'aan after the four righteous Khulafaa. Hadhrat Abdullaah bin Mas'ood (RA) frequented the home of Rasulullaah (sallAllaahu-alayhi-wa-sallam) so often that Hadhrat Abu Moosa Ash'ari (RA) mentioned that they thought he was a member of Rasulullaah (sallAllaahu-alayhi-wa-sallam)'s family. Hadhrat Umar (RA) also acknowledged that Hadhrat Abdullaah bin Mas'ood (RA) was proficient in Fiqh and Ahadeeth. Therefore, he appointed Hadhrat Abdullaah bin Mas'ood (RA) to be the leading authority of Ahadeeth in the newly occupied region of Iraq.

Rasulullaah (sallAllaahu-alayhi-wa-sallam) said that the person who desires to recite the Qur'aan as if it was just revealed, should recite according to the recitation of Hadhrat Abdullaah bin Mas'ood (RA). the books of Ahadeeth are filled with Rasulullaah (sallAllaahu-alayhi-wa-sallam)'s praises for Hadhrat Abdullaah bin Mas'ood (RA). Only a person guilty of bid'ah will ever criticise a noble personality like him. Rasulullaah (sallAllaahu-alayhi-wa-sallam) said, "If I was to appoint a deputy without any consultation, I would appoint Abdullaah bin Mas'ood (RA)."

Hereunder are a few of his rulings:

1) He never raised his hands to his ears when going into Ruku or when standing up from Ruku. An authentic hadith of Nasa'ee (Vol.1 Pg.158) states that he only raised his hands to his ears once during salaah (when beginning). Thereafter, he never raised them again during the salaah.

2) He was also of the opinion that Islaamic rulings can be based on the statements of the learned predecessors and on the deductions of reasoning (Ijtihaad) when a matter cannot be conclusively resolved by a study of the Qur'aan and Ahadeeth [Nasa'ee Vol.2 Pg.260]. Therefore, he was not amongst those who believed that, after the Qur'aan and Ahadeeth, they do not require anything else (Fiqh).

3) He greeted Rasulullaah (sallAllaahu-alayhi-wa-sallam) by shaking (whilst using) both hands. [Bukhari Vol.2 Pg.926]