O you who believe! call to witness between you when death draws nigh to one of you, at the time of making the will, two just persons from among you, or two others from among others than you, if you are travelling in the land and the calamity of death befalls you; the two (witnesses) you should detain after the prayer; then if you doubt (them), they shall both swear by Allah, (saying): We will not take for it a price, though there be a relative, and we will not hide the testimony of Allah for then certainly we should be among the sinners.

And Allah sets forth a parable of two men; one of them is dumb, not able to do anything, and he is a burden to his master; wherever he sends him, he brings no good; can he be held equal with him who enjoins what is just, and he (himself) is on the right path?