Scholars have deduced the reference to Hadrat Abu Bakr's (RA) caliphate from some verses of the Qur'aan. Al-Hasan al-Basri (RA), commenting on the verse: "O you who believe! Whoever from among you turns back from his religion (Islam), Allah will bring a people whom He will love and they will love Him; humble towards the believers, stern towards the disbelievers, fighting in the Way of Allah, and never afraid of the blame of the blamers. That is the Grace of Allah which He bestows on whom He wills. And Allah is All-Sufficient for His creatures' needs, All-Knower." (5:54) said, 'By Allaah, they are Abu Bakr and his companions. When some Arabs relinquished Islaam after the death of the Prophet (sallallaahu 'alaihi wa sallam), Abu Bakr and his Companions fought them until they returned back to Islaam.' (Seeratul Khulafaa ar-Raashideen radiallaahu 'anhum)