Evil is thou', and the worst evil is thou', which thou knowest it not. - Abū-Sa'īd Abul-Khayr

Freedom from lower qualities is an essential qualification required for spiritual progress.

What sweeter than this in the world!
Friend met friend and the lover joined his Beloved.
That was all sorrow, this is all joy
Those were all words, this is all reality.

If you wish that God should dwell in your heart, purify your heart from all save Him for the king will not enter a house filled with stores and furniture. He will only enter a heart which is empty of all save Himself.