What is the meaning of "أُكَفِّرُ" (I make atonement/expiation) as it appears in the saying of Job (peace be upon him): "Then I would return to my house, and make atonement for them both, for fear that they might have cursed God in their hearts"?

Ibn Hibban, Al-Hakim, and Al-Albani narrated the hadith: "He would expiate for them." The meaning of expiation for them is to give charity and the like, as an expiation for their mixing the remembrance of Allah with what is impermissible. Al-Tahawi said that this expiation is not for an oath, but rather for the speech in which Allah was mentioned inappropriately, out of fear that a general punishment might descend due to apparent sins that have not changed. Charity averts punishments and expiates sins, even if it is not from the sinners themselves, which is similar to the lifting of punishment from the Ummah through the supplication for forgiveness by some of its individuals.