The firstlings; either,
1. The first-born, which God reserved to himself, both at this time, and afterwards by an express law, Exodus 13:2 Numbers 3:13. Or,
2. The choicest and most eminent of the flock; for the best of any kind are oft called first-born, as Job 18:13 Jeremiah 31:19 Hebrews 12:23. The fat thereof was either,
1. Properly, the fat being properly now required by God, as afterwards was expressed, Exodus 29:13, Exodus 29:22, Leviticus 3:3. Or,
2. The best of them, as the word fat is often used, as Genesis 45:18, Genesis 49:20, Numbers 18:12 Nehemiah 8:10 Psalms 147:14. The Lord had respect, or, looked to him with a gracious eye, kindly accepted and owned him and his sacrifice, and testified this \Hebrews 11:4\ to Cain and all there present, either by express word, or by some visible sign; probably by consuming his sacrifice by fire from heaven, as the fathers generally think; whereby also God did afterwards frequently signify, his acceptance of sacrifices, as Leviticus 9:24, Judges 6:21, 1 Kings 18:38 1 Chronicles 21:26 2 Chronicles 7:1. Unto Abel's person, who was a truly good man; and then to his sacrifice, which was offered with faith in God's mercy and in the promised Mediator, Hebrews 11:4.