We speak of the real presence of the Lord Jesus Christ in the service as we know it now, and we seek to respond to him and serve him. We readily admit that there are times when this is difficult and the Lord does not seem to be present. Whether because of sin, fatigue or simply lack of faith, Jesus often seems to be far away. Though we continue on in Christian life and in service, we long for that day when we will see him face to face and be like him (1 Jn. 3:2). The communion service is a reminder of that day. It is a foreshadowing of the great marriage supper of the Lamb. It is an encouragement to faith and an impulse to a higher level of holiness. http://www.tenth.org/resource-library/articles/the-lord-s-supper
The past significance of the Lord's Supper is made clear by the word remembrance. In the Lord's Supper we look back to the Lord's death. We remember his substitutionary atonement, first of all; it is this that the broken bread, representing the Lord's broken body, and the wine, representing his shed blood, most clearly signify. Atonement has to with our being made right with God. Substitutionary means that this was achieved by the death of another in our place. http://www.tenth.org/resource-library/articles/the-lord-s-supper