The  Lord’s Supper was instituted by our Savior the night which He was betrayed and delivered to die for our sins on the cross (Matthew 26:20-30). We are not saved by partaking of the Supper. It is a memorial of the death of Christ that we may ever remember his sacrifice for us (I Corinthians 1:16).
Who may take the Lord’s Supper? Those who have trusted Jesus as their Savior and who have been baptized in obedience to His command. In the Great Commission, recorded in Matthew 28: 19-20, three things are very plain: first, we are to make disciples (the literal translation) of all nations: second, we are to baptize these converts in the name of the Father and of the Son and of the Holy Spirit; third, we are to teach these converts to observe the things Jesus has commanded us, one of those things commanded being the observance of the Lord’s Supper. The order Jesus gave is very plain: It is one, two, three. One, we must trust in Jesus and become a disciple of Jesus. Two, we are to be baptized, “buried with the Lord and raised with the Lord.” Three, we are to observe the things Christ has given us to keep, one of which is the Lord’s Supper.
This order of one, two, three is as much inspired as the content of the Great Commission. Before I have the privilege of taking the Lord’s Supper I must (first) be converted, I must (second) be baptized, then (third), I am ready to sit at the Lord’s table.