Is it permissible for one who vowed to slaughter a sheep and give it in charity to the poor and the needy to buy it slaughtered from the slaughterhouse given that the vow taker will not slaughter it by himself and that some parts of the slaughtered animal are missing, like the head, the guts and the fleece. If this is permissible, may he, because of bad financial conditions, divide the vow and offer half a sacrifice at a time and then the other half after a period of time given that the number of sheep he has vowed to offer is relatively big?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

This person should fulfill his vow according to the manner that he committed himself to. If he imposed upon himself to slaughter a sheep, then he has to do so. It does not free him of his liability to buy a ready-slaughtered sheep because the reality of this action is buying meat, not slaughtering a sheep.

This person is required to fulfill his vow whenever this is possible for him as long as he did not appoint a specific timing for doing so. If he is permanently unable to fulfill it, then he should offer an expiation for oath breaking.

Allaah Knows best.