Now this man ... - The money which was given for betraying the Lord Jesus was thrown down in the temple, and the field was purchased with it by the Jewish priests. See Matthew 27:5, Matthew 27:10, and the notes on that place. A man is said often to do a thing when he furnishes means for doing it. Compare Matthew 27:60, “And laid it (the body of Jesus) in his own new tomb, which he had hewn out in the rock.” That is, had caused to be hewn out. John 4:1, “when, therefore, the Lord knew how the Pharisees had heard that Jesus “made and baptized” more disciples than John.” Through his disciples, for Jesus himself baptized not, John 4:2. The same principle is recognized in law in the well-known maxim, “Qui facit per alium, facit per se.”
The reward of iniquity - The price which he had for that deed of stupendous wickedness - the betraying of the Lord Jesus.
And falling headlong - The word here rendered “headlong” - πρηνής prēnēs (Latin “pronus,” whence our English word “prone”) - means properly “bent forward, head-foremost”; and the idea is, that his position in hanging himself was such that when the cord broke he fell headlong, or fell forward on his face. This can easily be supposed if he threw himself from a rock or elevated place. He first hanged himself, and then fell and was burst asunder. See the notes on Matthew 27:5.