Musannaf Ibn Abi Shaybah

Hazrat Mak’hool states that when a person pays zakat in a certain month, and then in the same month he acquires some more wealth and spends it, then there is no zakat on the wealth he has spent. However, if in the month he paid zakat he acquired some wealth which remained with him for the entire month, then zakat must be paid on it. And if in the month he did not pay zakat, he acquired some wealth, then as soon as he benefits from it, zakat must be paid on it (it is not a condition for a year to pass over it).

Hazrat Ikrimah narrates that Hazrat Ibn Abbas (may Allah be pleased with them) was asked whether a person who receives some wealth (is zakat due on it during the year or not?). He replied: Zakat is due at the time he benefits from it.

Imam Zuhri states that when a person receives wealth and intends to spend it before the month in which he pays zakat, he should first pay its zakat and then spend it. But if he does not intend to spend it before the zakat month, then he should combine this wealth with his existing wealth and pay zakat on all of it at the same time. (He should not wait for a year to pass over this wealth.)