The colors green, red, black and white are important symbolically in Islam. They feature prominently in many flags of Muslim countries. The green symbolizes detachment from the world (zuhud). Enjoying worldly things is permitted but it should not be our focus or occupy our heart. Anything that causes us to forget Allah is dunya (worldly). Red is the color of the forger’s tool. It is to tolerate the trials of the world with patience and purify our souls. Black is the absence of worldly color and a symbol of detachment from the world. White is the color of hunger. We are commanded to fast. Even Adam and Hawa were ordered to fast from a particular tree in paradise. Summarized from a lecture by Shaykh Abdul Hakeem Murad