Are they, then, also to be admitted to this Supper who show themselves by their confession and life to be unbelieving and ungodly?

Heidelberg Catechism

Question 82. Are they, then, also to be admitted to this Supper who show themselves by their confession and life to be unbelieving and ungodly?

Answer. No, for thereby the covenant of God is profaned and His wrath provoked against the whole congregation;[1] therefore, the Christian Church is bound, according to the order of Christ and His Apostles, to exclude such persons by the Office of the Keys until they amend their lives.

[1] Ps 50:16-17; Isa 1:11-17, 66:3; Jer 7:21-23; Mt 7:6; 1 Cor 11:17-34; 2 Thes 3:6; Tit 3:10-11