I replied: That prayer was for old Jerusalem, which Christ sent his armies to destroy in 70 AD. The new covenant fulfilled the promise to David: that the fruit of his loin (Christ) would sit on his throne forever. Acts 2:22-36<<<
After studying Ps 122, I am beginning to believe that I may have misunderstood that passage. This is a part you didn't reference:
"Jerusalem is builded as a city that is compact together: Whither the tribes go up, the tribes of the Lord, unto the testimony of Israel, to give thanks unto the name of the Lord. For there are set thrones of judgment, the thrones of the house of David. Pray for the peace of Jerusalem: they shall prosper that love thee." (Ps 122:3-6 KJV)
Now I am beginning to believe that David is talking about New Jerusalem, the heavenly city on mount Sion. Jesus had promised his disciples that they would judge from twelve thrones:
"And Jesus said unto them, Verily I say unto you, That ye which have followed me, in the regeneration when the Son of man shall sit in the throne of his glory, ye also shall sit upon twelve thrones, judging the twelve tribes of Israel." (Mat 19:28 KJV)
Thrones and judgement are also mentioned at the first resurrection:
"And I saw thrones, and they sat upon them, and judgment was given unto them: and I saw the souls of them that were beheaded for the witness of Jesus, and for the word of God, and which had not worshipped the beast, neither his image, neither had received his mark upon their foreheads, or in their hands; and they lived and reigned with Christ a thousand years." (Rev 20:4 KJV)
I have no references that indicate there were so-called "thrones of judgement" in the days of David. Therefore, I believe he was talking about the thrones in New Jerusalem.
Philip