This question builds on a statement found in last weeks answer to the question, "Is God's kingdom yet to be established?"  The statement was that Christ would not set foot on earth again, rather, He would only meet the righteous in the air as is plainly taught in I Thessalonians 4:17, "Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord."  [For a copy of that article feel free to contact the address below].  The question that will be noticed in this articles boils down to this, "If Christ will not set foot on earth, what's the use in coming at all?"
    The answer to this question is seen in I Corinthians 15:24, "Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power."  Christ is returning so that he can deliver the kingdom (the already established church) to God, the Father.  To deliver something you must first go and receive it.  This will be done when Christ meets the living faithful in the air.
    The return of Christ to gather the faithful is not all that will happen on the day when Christ returns.  Things that will not happen are as follows:  A kingdom will not be setup for it already has been (Colossians 1:13,14), He will not come to offer another chance to those who are not Christians (Matthew 25:31-34; Hebrews 9:27), and He will certainly not return to give his body as a sacrifice again (Hebrews 9:28).  What will happen on that day?  All will be resurrected (John 5:28-29), judgment will come upon all people (John 12:48; Revelation 20:11-15), death will be destroyed (I Corinthians 15:26), the earth itself will be destroyed (II Peter 3:10-13), and faithful Christians will be rewarded (Colossians 3:2-4).
    There is no doubt that Christ will return again, and there should be no question about His purpose in doing so.  The day that He returns will not be merely a step along the way to establishing a kingdom, rather it will be a declaration of victory for those who are already in it.