Baptism and the Lord’s supper are ordinances of positive [explicit and definite] and sovereign institution. They are appointed by the Lord Jesus, the only lawgiver, to be continued in his church to the end of the world.1
1 Mt 28.19-20; 1Cor 11.26
These holy appointments are to be administered only by those who are qualified and called to do so, according to the commission of Christ.2