—if he were to swear by Allah, Allah would surely honor his oath. What, then, is the criterion?

The criterion is God-consciousness (taqwa). Allah says, “Indeed, the most honored of you in Allah’s sight is the most God-fearing” (Qur’an 49:13). Whoever is most mindful of Allah is the most honored before Him: Allah makes his affairs easy, answers his prayers, removes his distress, and upholds his oaths.

A person of this caliber will never swear to something that entails injustice toward anyone, nor will he presume upon Allah’s dominion. He only swears by Allah regarding matters that please Allah, trusting in Him—or, at the very least, in permissible matters, again trusting in Him.

We have already encountered the story of al-Rubayyiʿ, daughter of al-Naḍr, and her brother Anas ibn al-Naḍr. Al-Rubayyiʿ broke the incisor of a girl from the Anṣār, so the case was brought before the Messenger of Allah ﷺ. He ruled that al-Rubayyiʿ’s tooth be broken in retribution, for she had broken the other girl’s tooth. Her brother Anas protested, “O Messenger of Allah, will al-Rubayyiʿ’s tooth really be broken?” He replied, “Yes—Allah’s Book prescribes retaliation: a tooth for a tooth.” Anas then declared, “By Allah, her tooth shall not be broken!” He said this out of confidence in Allah and hope that He would grant relief and ease.

Thus he swore the oath—not to repudiate the Prophet’s ruling, but out of trust in Allah. Allah then guided the family of the injured girl, and they accepted compensation or forgave altogether. The Prophet ﷺ remarked, “Among Allah’s servants are those who, were they to swear by Allah, Allah would certainly honor their oath,” because they only swear concerning matters that please Allah, motivated by their good opinion of Him.