He was asked:

A man traded in cloth, selling it to another person at a specified profit and allowing him to pay the price in instalments. The debtor wishes to travel but has not provided a guarantor. May the creditor prevent him from travelling?

He replied:

If the debt is due and the debtor is able to repay it, the creditor may prevent him from travelling until he has recovered what he is owed. Likewise, if payment is deferred but falls due before the debtor’s return, the creditor may prevent him from travelling until he provides security, either through collateral that safeguards the amount owed or through a guarantor. If the debt does not fall due until after the debtor’s return, the scholars differ on the matter. And Allah knows best.