Is the sum of 22,0 pounds, which is in excess of the agreed-upon price for marriage furniture, considered a debt owed by the enquirer to his mother-in-law, and how should the amount of 1050 Saudi riyals, representing the cost of airline tickets paid by the enquirer for his mother-in-law, be settled, and is it permissible to repay the debt in Saudi riyals taking into account the change in the exchange rate?

Disputes of this nature require a Sharia (definition) judge or someone acting on his behalf to rule on them, as words, intentions, and events have an impact on the verdict.

The questioner's statement: "I considered my wife's mother's [money] a debt upon me, to be repaid whenever I wish" may establish the debt in his liability. His in-laws' action in purchasing the aforementioned furniture is considered an unauthorized transaction (فضولي), and the majority of jurists affirm the validity of an unauthorized purchase if approved by its owner. The questioner's silence and his use of the furniture suggest approval.

As for booking airplane tickets for the wife's mother, the questioner's right to the amount in Saudi Riyals is established, and it should be returned to him with an equivalent amount in Riyals or its equivalent in another currency at its value at the time the debt is paid.