Heidelberg Catechism: Lord’s Day 25

Q: 65. Since then we are made partakers of Christ and all his benefits by faith only, whence does this faith proceed?
A: From the Holy Spirit, who works faith in our hearts by the preaching of the gospel, and confirms it by the use of the sacraments.

Q: 66. What are the sacraments?
A: The sacraments are holy visible signs and seals, appointed of God for this end, that by the use thereof, he may the more fully declare and seal to us the promise of the gospel, that is, that he grants us freely the remission of sin, and life eternal, for the sake of that one sacrifice of Christ, accomplished on the cross.

Q: 67. Are both word and sacraments, then, ordained and appointed for this end, that they may direct our faith to the sacrifice of Jesus Christ on the cross, as the only ground of our salvation?
A: Yes, indeed: for the Holy Spirit teaches us in the gospel, and assures us by the sacraments, that the whole of our salvation depends upon that one sacrifice of Christ which he offered for us on the cross.

Q: 68. How many sacraments has Christ instituted in the new covenant, or testament?
A: Two: namely, holy baptism, and the holy supper.

1. The Holy Spirit operates in both the preaching of the Gospel and in the sacraments. Most Protestants would say yes to the first, but no to the second. This also means that just as the Holy Spirit works only in the elect via the preached word, so He works only in the elect via the sacraments.

2. The sacraments are there to assure us that Christ’s work upon the cross is sufficient for our salvation. In other words, the sacraments cause us to look away from ourselves to the cross. They are not there so that we might look into our hearts or into some past experience.