WLC Q.173: May any who profess the faith, and desire to come to the Lord’s supper, be kept from it?
Such as are found to be ignorant or scandalous, notwithstanding their profession of the faith, and desire to come to the Lord’s supper, may and ought to be kept from that sacrament, by the power which Christ hath left in his church, (1 Cor. 11:27–31, Matt. 7:6, 1 Cor. 5, Jude 23, 1 Tim. 5:22) until they receive instruction, and manifest their reformation. (2 Cor. 2:7)