Praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.

The fundamental Islamic principle is the obligation to fulfill rights to their owners. Among these rights is the right of the hired worker (ajir), because utilizing a hired worker without compensation is a clear injustice. The Messenger of Allah (peace be upon him) said: "There are three whose adversary I shall be on the day of resurrection: a man who gave a promise in my name then acted faithlessly; a man who sold a free man and enjoyed the price he received for him; and a man who hired a servant and, after receiving full service from him, did not give him his wages.” [Narrated by Bukhari].

A delivery worker is considered a hired person who performs a service of delivering goods to those who request them. Therefore, it is not permissible to diminish his right by stipulating that he will not be paid his wage if he delays in completing the work. However, if a deduction of a known portion of the wage is stipulated, then this is permissible, as stated by some Hanafis and Majallat al-Ahkam al-Adliyyah (Also known as the Ottoman Code of Civil Laws). Imam al-Marghinani al-Hanafi (may Allah have mercy on him) said: "If he said: 'If you sew it today, it's for one dirham, and if you sew it tomorrow, it's for half a dirham...' Abu Yusuf and Muhammad said: Both conditions are permissible" [Al-Hidayah, Vol. 3/P.244].

Moreover, if the delivery worker stipulates this condition upon himself, it is permissible, as this falls under the category of voluntary charitable act (tabarru').

It is important to note that some delivery companies impose this condition, thereby depriving the delivery worker of his right despite the effort he exerted. This is forbidden (haram).

In conclusion, it is forbidden to stipulate the deprivation of a worker's wage if he is delayed in delivery, unless he voluntarily agrees to it. However, it is permissible to stipulate the deduction of a known portion of the wage in case of his delay. And Allah the Almighty knows best.