[Isaiah 9:6-7 KJV] 6 For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace. 7 Of the increase of [his] government and peace [there shall be] no end, upon the throne of David, and upon his kingdom, to order it, and to establish it with judgment and with justice from henceforth even for ever. The zeal of the LORD of hosts will perform this.
The Lord Jesus Christ will sit on the throne of David in the kingdom on earth.
Psalm 132:11 The LORD hath sworn in truth unto David; he will not turn from it; Of the fruit of thy body will I set upon thy throne.
This Psalm is saying that the fruit of David's body will sit on David's throne. Christ Jesus is the seed of David according to the flesh (Romans 1:3).
Acts 2:29 Men and brethren, let me freely speak unto you of the patriarch David, that he is both dead and buried, and his sepulchre is with us unto this day.
In the above verse Peter is speaking of David being dead.
Acts 2:30 Therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, he would raise up Christ to sit on his throne;
Peter is recounting Christ's resurrection and saying Christ rose to sit on David's throne. The resurrection of Christ assured Israel that Christ is alive and will come back to save Israel:
[Luke 12:32 KJV] 32 Fear not, little flock; for it is your Father's good pleasure to give you the kingdom.
The little flock is the believing remnant of Israel who was promised the Davidic kingdom on earth.
[Matthew 4:17 KJV] 17 From that time Jesus began to preach, and to say, Repent: for the kingdom of heaven is at hand.
Jesus preached the kingdom of heaven was at hand. The kingdom of heaven is the prophetic kingdom on earth, in which, Christ will rule with believing Israel.
[Acts 3:19 KJV] 19 Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord;
National Israel will have their sins blotted out at Christ's coming.
[1Peter 3:21 KJV] 21 The like figure whereunto [even] baptism doth also now save us (not the putting away of the filth of the flesh, but the answer of a good conscience toward God,) by the resurrection of Jesus Christ:
Peter was saying they could know their water baptism saved them by the resurrection.
All of the above verses speak of Israel's assurance of their salvation by the resurrection.
The Lord Jesus Christ will sit on the throne of David in the kingdom on earth.
Psalm 132:11 The LORD hath sworn in truth unto David; he will not turn from it; Of the fruit of thy body will I set upon thy throne.
This Psalm is saying that the fruit of David's body will sit on David's throne. Christ Jesus is the seed of David according to the flesh (Romans 1:3).
Acts 2:29 Men and brethren, let me freely speak unto you of the patriarch David, that he is both dead and buried, and his sepulchre is with us unto this day.
In the above verse Peter is speaking of David being dead.
Acts 2:30 Therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, he would raise up Christ to sit on his throne;
Peter is recounting Christ's resurrection and saying Christ rose to sit on David's throne. The resurrection of Christ assured Israel that Christ is alive and will come back to save Israel:
[Luke 12:32 KJV] 32 Fear not, little flock; for it is your Father's good pleasure to give you the kingdom.
The little flock is the believing remnant of Israel who was promised the Davidic kingdom on earth.
[Matthew 4:17 KJV] 17 From that time Jesus began to preach, and to say, Repent: for the kingdom of heaven is at hand.
Jesus preached the kingdom of heaven was at hand. The kingdom of heaven is the prophetic kingdom on earth, in which, Christ will rule with believing Israel.
[Acts 3:19 KJV] 19 Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord;
National Israel will have their sins blotted out at Christ's coming.
[1Peter 3:21 KJV] 21 The like figure whereunto [even] baptism doth also now save us (not the putting away of the filth of the flesh, but the answer of a good conscience toward God,) by the resurrection of Jesus Christ:
Peter was saying they could know their water baptism saved them by the resurrection.
All of the above verses speak of Israel's assurance of their salvation by the resurrection.