Ma'arif al-Qur'an
Mufti Muhammad ShafiInjunction [ 5]وَلَا تَمْنُنْ تَسْتَكْثِرُ (...and do no favour [ to anyone merely ] to ask more [ in exchange ]....74:6). In other words, no gift should be given to anyone seeking to get back in return more than what was given. This indicates that it is reprehensible to give to someone a gift with the intention that the person will give him a higher gift. Although it seems to be allowed, by another verse of the Qur'an, for common people, yet it is reprehensible and morally unrighteous - especially for the Holy Prophet, it is unlawful, as explained by Ibn ` Abbas