Amir (al-Sha'bi) was asked about a man who vowed that if he entered the house of so-and-so he would free two slaves from the descendants of Isma'il, and then he entered his house. He said: There is no expiation for it. The man said: I cannot find the two of them. He said: Then fast four consecutive months, two months for each slave; perhaps it will be some expiation.