One of the great themes of the Bible is the Kingdom of God. God is King and He has ruled from all eternity, and will rule forever. The Lord has permitted some enemies to exist in His kingdom, but one day He will destroy all of His enemies. His people will then inherit the kingdom and He will be with them forever in the eternal kingdom in which there will be no enemies, no wicked people, and no sin at all.
Before we, His people, can inherit the kingdom of God we must be changed. That change will take place at the resurrection when Jesus comes (1 Corinthians 15:50-58, cf. vss. 20-23). When He comes all His enemies will be destroyed. The last enemy that will be destroyed is death (See vv. 24-26). In light of all this we must live for the Lord. Paul put it this way at the end of this passage, at the end of 1 Corinthians 15…

Therefore, my beloved brethren, be steadfast, immovable, always abounding in the work of the Lord, knowing that your labor is not in vain in the Lord.