In 1 Corinthians 11:26, Paul wrote that, "Whenever you eat this bread and drink this cup, you proclaim the Lord's death until He comes." The Lord's Table is a time to remember, celebrate and proclaim the great culmination of God's eternal plan to redeem us, on the Cross of Jesus Christ. But when we come to the table, we do more than just remember, celebrate and proclaim. We also partake. As we put our faith in the things that the Bread and the Cup signify (the body and the blood of Jesus), God has promised to strengthen our faith and our lives by the grace that we remember and proclaim. We celebrate Communion every week because we need the strength and grace of Christ every week. We come hungry and thirsty, confessing that only He can feed us and quench our thirst.
In the same chapter in 1 Corinthians (chapter 11, verse 27), Paul gives a strong warning to the church about taking communion in an "unworthy way", and tells us to examine ourselves when we eat the Bread and drink from the Cup. He means that when we come, we must always come in faith, trusting the grace and mercy of Jesus for forgiveness and strength in all of life. To come in faith is to come as children, implicitly trusting in the goodness of our Father and all that He supplies.
This means that the only ones who should participate in Communion are the ones who have already been saved by His grace through real, living faith in Jesus Christ. The Table is a time when God gathers His redeemed and reborn Children and feeds their souls with His all-sufficient grace. If you haven't yet been saved by God's grace through faith in Jesus Christ and His death and resurrection - if you haven't yet been reborn by His Holy Spirit, it's important to wait to participate in Communion. If you have been saved, and trusted Christ alone for salvation, it's important to feast regularly at the Table, and to feast "worthily", as Paul says. Worthy feasting at the Lord's Table doesn't mean coming without sin. It means coming with sin, as sinners, confessing our sin and trusting that Christ's work on the Cross is everything that we need.  If you are a redeemed, reborn Child of the King, then whoever you are, and wherever you are from, we welcome you to come, join us at the Lord's Table and let Him feed you with True Bread and True Drink.