2Sa 7:16 And thine house and thy kingdom shall be established for ever before thee: thy throne shall be established for ever.
2Sa 7:17 According to all these words, and according to all this vision, so did Nathan speak unto David.

One day we will see the literal fulfilment of this promise. One day Jesus will return as King of King's and Lord of Lord's. He will sit upon the throne of David. He will rule the kingdom forever.

Paul speaks of this day in 1st Corinthians 15:24-28.

1Co 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.
1Co 15:25 For he must reign, till he hath put all enemies under his feet.
1Co 15:26 The last enemy that shall be destroyed is death.
1Co 15:27 For he hath put all things under his feet. But when he saith all things are put under him, it is manifest that he is excepted, which did put all things under him.
1Co 15:28 And when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him, that God may be all in all.

One day, Jesus will deliver the kingdom to His Father. One day, the curse will be removed from this earth. All of God's creation will be subdued. All things will be put under him, that God may be all in all.

Let me quote Bro. Carl Sadler on these verses. "The world has been rebellious to our Lord, but He shall bring all men to bow before Him. Some will be subdued by His love. These are the saved ones. Others will be subdued by His power. These are the lost. When Jesus has brought all men under His power and control, He will deliver all to God the Father for an eternal reign."