M5:3674 — می‌فشاند برگ زرد از شاخ دل / تا بروید برگ سبز متصل

This couplet uses the classic seasonal metaphor of a tree to explain the spiritual function of sorrow. The preceding verses (M5:3672–73) have already established that the 'thought of grief' (fikr-i gham) is not an enemy to be expelled, but a guest who arrives to perform a vital service. It acts as a brusque housekeeper, sweeping the 'house' of the heart clean of 'others' (ghayr)—that is, everything other than God.

The couplet sharpens this image: the heart is a tree, and sorrow is the wind that shakes its branches. This action isn't destructive; it's a necessary pruning. The 'yellow leaves' (barg-i zard) represent old joys, attachments, and spiritual states that have become dry and lifeless. By shaking them loose, sorrow clears the way for 'green leaves' (barg-i sabz) to sprout. The key word is muttaşil (continuous, connected), suggesting that this new growth is not just a fleeting replacement but a vibrant, unbroken connection to the divine Source, the 'origin of good' mentioned in the previous line.