The Test of Iblis and Adam

One mark of Adam from eternity was this, that the angels should lay their heads (on the ground) before him, because it was his place (proper to his dignity). 
Another mark was that Iblís, saying, “I am the king and chief,” should not lay down his head before him.
 But if Iblís too had become a worshipper (of Adam), he (Adam) would not have been Adam: he would have been another. 
At once the worship of every angel is the test of him, and the denial (of him) by that enemy (Iblís) is the proof of him. 
At once the acknowledgment (made) by the angels is witness for him, and the disbelief of that petty cur (Iblís) is witness for him.

The Masnawi - Vol 2, 2120