The pastors and church leaders who wrote the doctrinal standards for our church urged all believers to take time to prepare themselves in advance for celebrating the Lord’s Supper. How do we do that? Question 171 of the Westminster Larger Catechism spells this process out in detail:
Question: How are they that receive the sacrament of the Lord’ s supper to prepare themselves before they come to it?
Answer: They that receive the sacrament of the Lord’ s supper are, before they come, to prepare themselves in advance, 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 brothers, (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).
Here is a link to a lovely prayer to reflect upon and pray through as you prepare your heart to take Communion:
2Cherish2Commend 