The Heidelberg Catechism: Lord's Day 25
65. Question: Since then faith alone makes us share in Christ and all His benefits, where does this faith come from?
Answer: From the Holy Spirit, who works it in our hearts by the preaching of the gospel, and strengthens it by the use of the sacraments.
 John 3:5; I Cor. 2:10-14; Eph. 2:8; Phil. 1:29.  Rom. 10:17; I Pet. 1:23-25.  Matt. 28:19, 20; I Cor. 10:16.
66. Question: What are the sacraments?
Answer: The sacraments are holy, visible signs and seals. They were instituted by God so that by their use He might the more fully declare and seal to us the promise of the gospel. And this is the promise: that God graciously grants us forgiveness of sins and everlasting life because of the one sacrifice of Christ accomplished on the cross.
 Gen. 17:11; Deut. 30:6; Rom. 4:11  Matt. 26:27, 28; Acts 2:38; Heb. 10:10.
67. Question: Are both the Word and the sacraments then intended to focus our faith on the sacrifice of Jesus
Christ on the cross as the only ground of our salvation?
Answer: Yes, indeed. The Holy Spirit teaches us in the gospel and assures us by the sacraments that our entire salvation rests on Christ's one sacrifice for us on the cross.
 Rom. 6:3; I Cor. 11:26; Gal. 3:27.
68. Question: How many sacraments has Christ instituted in the new covenant?
Answer: Two: holy baptism and the holy supper.
 Matt. 28:19, 20; I Cor. 11:23-26.
The Heidelberg Catechism: Lord's Day 23
59. Question: But what does it help you now that you believe all this?
Answer: In Christ I am righteous before God and heir to life everlasting.
 Hab. 2:4; John 3:36; Rom. 1:17; 5:1, 2.60.
Question: How are you righteous before God?
Answer: Only by true faith in Jesus Christ. Although my conscience accuses me that I have grievously sinned
against all God's commandments, have never kept any of them, and am still inclined to all evil, yet God, without any merit of my own, out of mere grace, imputes to me the perfect satisfaction, righteousness, and holiness of Christ. He grants these to me as if I had never sinned nor been a sinner, and as if I myself had accomplished all the obedience which Christ has rendered for me, if only I accept this gift with a believing heart.
 Rom. 3:21-28; Gal. 2:16; Eph. 2:8, 9; Phil. 3:8-11.  Rom. 3:9, 10.  Rom. 7:23.  Deut. 9:6; Ezek. 36:22; Tit. 3:4, 5.  Rom. 3:24; Eph. 2:8.  Rom. 4:3-5; II Cor. 5:17-19; I John 2:1, 2.  Rom. 4:24, 25; II Cor. 5:21.  John 3:18; Acts 16:30, 31; Rom. 3:22.
61. Question: Why do you say that you are righteous only by faith?
Answer: Not that I am acceptable to God on account of the worthiness of my faith, for only the satisfaction, righteousness, and holiness of Christ is my righteousness before God. I can receive this righteousness and make it mine in no other way than by faith alone.
 I Cor. 1:30, 31; 2:2.  Rom. 10:10; I John 5:10-12.
The Heidelberg Catechism: Lord's Day 7
20. Questions: Are all men, then, saved by Christ just as they perished through
Answer: No. Only those are saved who by a true faith are grafted into Christ and accept all His benefits.
 Matt. 7:14; John 1:12; 3:16, 18, 36; Rom. 11:16-21.
21. Question: What is true faith?
Answer: True faith is a sure knowledge whereby I accept as true all that God has revealed to us in His Word. At the same time it is a firm confidence that not only to others, but also to me, God has granted forgiveness of sins, everlasting righteousness, and salvation, out of mere grace, only for the sake of Christ's merits. This faith the Holy Spirit works in my heart by the gospel.
 John 17:3, 17; Heb. 11:1-3; James 2:19.  Rom. 4:18-21; 5:1; 10:10; Heb. 4:16.  Gal. 2:20.  Rom. 1:17; Heb. 10:10.  Rom.3:20-26; Gal. 2:16; Eph. 2:8-10.  Acts 16:14; Rom. 1:16; 10:17; I Cor. 1:21.
22. Question: What, then, must a Christian believe?
Answer: All that is promised us in the gospel,  which the articles of our catholic and undoubted Christian faith teach us in a summary.
 Matt. 28:19; John 20:30, 31.
23. Question: What are these articles?
Answer: III.1.I believe in God the Father almighty, III.1. Creator of heaven and earth. III.2.I believe in Jesus Christ, III.2.His only begotten Son, our Lord; III.3.He was conceived by the Holy Spirit, III.3.born of the virgin Mary; III.4.suffered under Pontius Pilate, III.4.was crucified, dead, and buried; III.4.He descended into hell; III.5.On the third day He arose from the dead; III.6.He ascended into heaven, III.6.and sits at the right hand III.6.of God the Father almighty; III.7.from there He will come to judge III.7.the living and the dead. III.8.I believe in the Holy Spirit; III.9.I believe a holy catholic Christian church, III.9.the communion of saints; III.10.the forgiveness of sins; III.11.the resurrection of the body; III.12.and the life everlasting.
The Heidelberg Catechism
Lord's Day 1