God gives us signs and seals to confirm his promises to us and to strengthen our faith
Belgic Confession Article 33 - The Sacraments: We believe that our good God, mindful of our crudeness and weakness, has ordained sacraments for us to seal his promises in us, to pledge his good will and grace toward us, and also to nourish and sustain our faith. He has added these to the Word of the gospel to represent better to our external senses both what he enables us to understand by his Word and what he does inwardly in our hearts, confirming in us the salvation he imparts to us. For they are visible signs and seals of something internal and invisible, by means of which God works in us through the power of the Holy Spirit. So they are not empty and hollow signs to fool and deceive us, for their truth is Jesus Christ, without whom they would be nothing. Moreover, we are satisfied with the number of sacraments that Christ our Master has ordained for us. There are only two: the sacrament of baptism and the Holy Supper of Jesus Christ.