It occurred to me today (in preparation for speaking to some folks about this) that it might be very helpful for people to have a handy chart for easily comparing the Reformed faith with official Roman Catholic teaching on a number of doctrines (comparing the Roman Catholic catechism with the Reformed confessions), and then seeing what Scripture has to say about it. So, references in the Roman side are to paragraph numbers in the RCC Catechism, and the standard abbreviations in the Reformed standards should be easily recognizable. I have concentrated on the most important issues. No doubt there are others I have missed. The format is first the Roman Catholic teaching, then the Reformed teaching, then the Scriptural teaching.
I. On Scripture: while Scripture is inspired by God, tradition and the pope have equal authority. See 891 of the Catechism.
Scripture alone is the infallible rule of faith and practice. See BC, article 7, WCF 1.
2 Timothy 3:16, 1 Thessalonians 2:13, 1 John 5:9
II. On Mary: She is Advocate, Helper, Benefactress, and Mediatrix (Cat. 969). She continues to intercede for us in heaven.
Jesus is our one and only High Priest. We need no other Mediatrix save Christ. (BC 21, HC 18, WCF 8, LC 36)
Phil. 3:1-9, 1 Cor. 2:1-2, Heb. 7:26-8:6, 9:11-14, 9:25-10:14
III. On justification: happens at baptism (1987, 1992), involves sanctification (1989, 1995), can be lost (1446).
Justification happens at time-point of faith, does not involve sanctification, and cannot be lost (BC 22-24, HC 60, WCF 11, LC 70-73)
1 Peter 3:21, Romans 3-4, 8
IV. Baptism regenerates (1213).
Baptism is a sign and seal of salvation, not salvation itself (BC 34, WCF 28). We are saved by the thing signified (Christ’s blood), not by the sign itself.
1 Peter 3:21, Colossians 2:11-13
V. The Lord’s Supper: transubstantiation (1373-1378), which results in the worship of the bread and wine.
The Lord is present spiritually only (HC 78-80, WCF 29)
Matthew 26:26-29, Mark 14:22ff., Luke 22:19ff, 1 Cor. 11:24ff.
VI. Purgatory: further purification might be needed after death (1030-1032)
Only two places for souls separated from the body (WCF 32.1)
Luke 23:39-43, 1 Cor. 3:10-15