One of the conditions for the obligation of zakah is the completion of the lunar year.

The Shaykh : The point to consider—may Allah reward you—is that one of the conditions of zakah is the completion of the lunar year. In the hadith of the Prophet (peace and blessings be upon him): . So if a person inherits money from someone, a relative of his who died and he was his heir, and he inherited ten thousand riyals in the month of Muharram. And in the month of Dhul-Qa'dah he bought a house with it, for ten thousand riyals. Does he owe zakah? O people, ten thousand riyals! It is the nisab. Why? Because its lunar year has not been completed. And one of the conditions for the obligation of zakah is the completion of the lunar year, except for one thing, meaning, from what there is a need to explain, otherwise there are other exceptions, and that is the profit of trade. The lunar year of the profit of trade is the lunar year of its principal. The lunar year of the profit of trade is the lunar year of its principal. An example of this: A man bought land for trade for ten thousand riyals. And his purchase of it was in Muharram, meaning: he owned ten thousand riyals, and immediately he bought land for trade with it. In Dhul-Hijjah, in Dhul-Hijjah, the value of the lands increased, and the value of the land he bought for ten thousand riyals reached twenty thousand riyals. Is zakah due on the ten thousand riyals when the lunar year of the ten thousand is completed, or on the twenty thousand? On the twenty thousand. - Pay attention to this, my brother -. The profit follows the principal. It has no lunar year of its own; its lunar year is the lunar year of its principal.