Is the understanding between the father and his son regarding the repayment of the borrowed money, which the son claimed was a gift, in exchange for the father lending his son new money, free from usury?

The father's procrastination in repaying the loan despite having the money is an injustice, according to the Prophet, peace and blessings be upon him, who said: "Procrastination by a rich person is an injustice." The loan must be repaid, and an apology should be offered to the father. The father's agreement to lend his son money to buy land after the previous loan has been repaid is permissible and does not constitute usury.