25 And it came to pass the same night, that the LORD said unto him, Take thy father's young bullock, even the second bullock of seven years old, and throw down the altar of Baal that thy father hath, and cut down the grove that is by it:
Then the man, instructed and foreknowing what was to be, observes the heavenly mysteries, and therefore, according to the warning, killed the bull destined for idols by his father, and himself offered to God another bull seven years old. By doing this he most plainly showed that after the coming of the Lord all Gentile sacrifices should be done away and that only the sacrifice of the Lord’s passion should be offered for the redemption of the people. For that bull was, in a type, Christ, in whom, as Isaiah said, dwelled the fullness of the seven gifts of the Spirit. This bull Abraham also offered when he saw the day of the Lord and was glad. He it is who was offered at one time in the type of a kid, at another in that of a sheep, at another in that of a bull. Of a kid, because he is a sacrifice for sin; of a sheep, because he is an unresisting victim; of a bull, because he is a victim without blemish.
[AD 397] Ambrose of Milan on Judges 6:25-27