The Heidelberg Catechism: Lord's Day 15
37. Question: What do you confess when you say that He suffered?
Answer: During all the time He lived on earth, but especially at the end, Christ bore in body and soul the wrath of God against the sin of the whole human race. Thus, by His suffering, as the only atoning sacrifice, He has redeemed our body and soul from everlasting damnation, and obtained for us the grace of God, righteousness, and eternal life.
 Is. 53; I Tim. 2:6; I Pet. 2:24; 3:18.  Rom. 3:25; I Cor. 5:7; Eph. 5:2; Heb. 10:14; I John 2:2; 4:10.  Rom. 8:1-4; Gal. 3:13; Col. 1:13; Heb. 9:12; I Pet 1:18, 19.  John 3:16; Rom. 3:24-26; II Cor. 5:21; Heb. 9:15.
38. Question: Why did He suffer under Pontius Pilate as judge?
Answer: Though innocent, Christ was condemned by an earthly judge, and so He freed us from the severe judgment of God that was to fall on us.
 Luke 23:13-24; John 19:4, 12-16.  Is. 53:4, 5; II Cor. 5:21; Gal. 3:13.
39. Question: Does it have a special meaning that Christ was crucified and did not die in a different way?
Answer: Yes. Thereby I am assured that He took upon Himself the curse which lay on me, for a crucified one was cursed by God.
 Deut. 21:23; Gal. 3:13.