Charles Ellicott Commentary Isaiah 58:6

"Is not this the fast that I have chosen: to loose the bonds of wickedness, to undo the bands of the yoke, and to let the oppressed go free, and that ye break every yoke?" — Isaiah 58:6 (ASV)

To loose the bands of wickedness. —The words do not exclude abstinence from food as an act of discipline and victory over self-indulgence, but declare its insufficiency by itself. So in the practice of the ancient Church fasting and almsgiving were closely connected, as indeed they are in Matthew 6:1; Matthew 6:16. The history of the emancipation of the slaves and of their subsequent return to bondage presents a curious illustration of the prophet’s words (Jeremiah 34:8–22). The truth which he proclaimed was recognised in the hour of danger and forgotten in that of safety. Compare to Joel 2:13.

To undo the heavy burdens. —Literally, the thongs of the yoke, the leather straps which fastened the yoke on the head of the oxen as they ploughed. Again we trace an echo of the thought and almost of the phraseology in our Lord’s teaching (Matthew 11:29–30; Matthew 23:4). The Pharisees who fasted laid heavy burdens on men’s shoulders. He, who was thought not to fast, relieved them of their twofold yoke of evil selfishness and ceremonial formalism.