Charles H. Spurgeon on Psalms 40:6

Here David goes beyond himself, and speaks the language of David's Son. This was naturally suggested by God's wonderful works, and innumerable thoughts of love to man.

1. The sacrifices that were not required. These were the sacrifices and burnt offerings under the law. (a) When required? From Adam to the coming of Christ. (b) When not required? (c) Why required before? As types of the one method of redemption. (d) Why not now required? Because the great Antitype had come.

2. The sacrifice that was required. This was the sacrifice offered on Calvary. (a) It was required by God by his justice, his wisdom, his faithfulness, his love, his honour, his glory. (b) It was required by man to give him salvation and confidence in that salvation. (c) It was required for the honour of the moral government of God throughout the universe.

3. The person by whom this sacrifice was offered. Mine ears hast thou opened. This is the language of Christ, prospectively denoting —(a) Knowledge of the sacrifice required. (b) Consecration of himself as a servant for that end.  —George Rogers.