Acts 8:23 - Matthew Poole's English Annotations on the Holy Bible

The gall of bitterness; the same with gall and wormwood, Deuteronomy 29:18: or gall and bitterness; signifying a very bad constitution and disposition of soul or mind, such as may be compared unto that meat which the gall of any creature hath corrupted. And for Simon Magus to be in the gall of bitterness, is yet worse than to have the gall of bitterness in him; as to be born in sin, which the Pharisees upbraided the blind man with, 1 Thessalonians 11:34, denotes more intended thereby than that he had sin from his birth in him: thus David bewails that he was shapen in iniquity, Psalms 51:5 and thus may those expressions of St. Paul be understood, of being in the flesh, and being in the Spirit, Romans 8:9. This also shows (if any sensible or outward thing could show it) what a bitter and poison my thing sin is, no gall so bitter, no poison so deadly. The bond of iniquity; either the judgment St. Peter had threatened to deter him from sin was this bond, or his sin itself might be rather so called: the we read of the bands of wickedness, Isaiah 58:6. One sin is twisted with another, hard to be severed or broken, and draws on judgment powerfully.