Beloved, the figure “settled on his lees” here depicts that of vinegar which was supposed to be made into wine but had settled for too long on the lees. I believe that this describes the same spiritual state as “resting at ease in Zion,” which is a condition that thousands upon thousands of Christians are in today … and don’t even realize it!
“Lees” in the church today bespeaks of the dregs of religion from which we must be siphoned or risk becoming the spiritual equivalent of wine vinegar. Lees are dead yeast. Jesus warned the disciples to “beware of the yeast of the Pharisees,” and that was speaking about the dead traditions and teachings of men which are often handed down from one generation to the next for many generations. These lees can also just be things that we have embraced as truth but which are not true, beloved. If we are not eventually siphoned off from these things, then we can become spiritual vinegar instead of new wine, this vinegar representing a sourness in heart and an insensitivity to the Spirit, even a particular insensitivity and lack of responsiveness to the word (and the workers) sent by God to help move us from the lees on into a new wineskin.