What is the ruling on the penalty clause resulting from a worker's delay in completing the agreed-upon work, or from a delay by the one whose turn it is to pay the agreed-upon association amount?

It is permissible to impose a penalty clause on a worker for being late, due to the harm incurred by the employer because of their delay. However, fairness must be observed in it without exaggeration, and an estimation that preserves the rights of both parties must be made. As for the joint association, if one of them delays payment and is penalized with an increase, it is not permissible, because it is a loan, and loans are not subject to penalties.