In Jude 21 Jude is exhorting us unto "Looking for the mercy of our Lord Jesus Christ unto eternal life" and if you follow this principle of the believer's duty to be waiting for the Lord Jesus' return, through the New Testament, you will find that it is always connected to the Christian's holiness. Peter, in the third chapter of his second epistle speaks of the consummation of the earth by fire and he asks; "What manner of persons ought we to be in all holy conversation (lifestyle) and Godliness, looking for and hasting unto the coming day of God? The Lord Jesus warns us at the end of the 14th chapter of Mark's gospel to "Watch" for no man knows that day and the hour. These passages teach us that a Christian cannot advance in Holiness unless we are continually looking for the second coming of our Lord Jesus Christ. The Christian can endure suffering because we know that there is an eternal reward connected to our suffering(Romans 8:18). The Christian can overcome sin because we know that one day we will be without sin (1John 3:2-3). We can resist the devil by reminding him of his sure and eternal demise when our Lord Jesus returns (Rev. 20:3). We can endure persecution knowing that the Lord Jesus Christ will perfectly judge all men in the end (Matt. 25:31-33), therefore we do not have to seek our vindication in this world for the Lord Jesus will defend us in the end. So I urge you to be continually waiting and watching for that great day when our Lord Jesus Christ will return to the earth. Every believer innately has this desire in him, by the work of the Holy Spirit, because we are waiting for the one we love and at the same time we must daily develop this constant activity of Looking for our coming Lord.