251. The commandment to tread in humbleness.

In these verses (15:88, 17:24, 26:215) of the Quran we see the commandment for people to lower their wings.

This refers to humbleness.

When the wings are spread the birds soar to their heights, when they lower their wings they come down, hence spreading the wings is referred to as arrogance and lowering them is referred to as humbleness in the Arabic language