WLC Q.171: How are they that receive the sacrament of the Lord’s supper to prepare themselves before they come unto it?
They that receive the sacrament of the Lord’s supper are, before they come, to prepare themselves thereunto, by examining themselves (1 Cor. 11:28) of their being in Christ, (2 Cor. 13:5) of their sins and wants; (1 Cor. 5:7, Exod. 12:15) of the truth and measure of their knowledge, (1 Cor. 11:29) faith, (1 Cor. 13:5, Matt. 26:28) repentance; (Zech. 12:10, 1 Cor. 11:31) love to God and the brethren, (1 Cor. 10:16–17, Acts 2:46–47) charity to all men, (1 Cor. 5:8, 1 Cor. 11:18,20) forgiving those that have done them wrong; (Matt. 5:23–24) of their desires after Christ, (Isa. 55:1, John 7:37) and of their new obedience; (1 Cor. 5:7–8) and by renewing the exercise of these graces, (1 Cor. 11:25–26,28, Heb. 10:21–22,24, Ps. 26:6) by serious meditation, (1 Cor. 11:24–25) and fervent prayer. (2 Chron. 30:18–19, Matt. 26:26)