Is zakat due on an amount of 100 dinars saved monthly from one's salary with the intention of buying land to build a house?

Zakat is obligatory on the amount available in the bank for purchasing land if a hawl (a lunar year) has passed on it and it has reached the nisab (minimum threshold), based on the statement of Ibn Umar: "Whoever benefits from money owes no zakat on it until a hawl passes on it," and based on the Prophet's (peace be upon him) saying: "If you have twenty dinars and a hawl passes on them, then a half dinar is due on them, and what exceeds that is calculated proportionally."