John Gill Commentary Psalms 78:54

"And he brought them to the border of his sanctuary, To this mountain, which his right hand had gotten." — Psalms 78:54 (ASV)

And he brought them to the border of his sanctuary: Of the land of Canaan, which the Lord had sanctified, and set apart for them; and of Jerusalem, the holy city, the city of the great God, and of the temple where his residence was to be; so the Targum, "to the border of the place of the house of his sanctuary."

even to this mountain, which his right hand purchased: The mount Moriah, on which the temple was built; this psalm being composed, as Aben Ezra and Kimchi think, after it was made known to David, by the prophet Gad, the place where the temple should be built; namely, on the very mountain, on part of which David had his palace; and this was obtained and possessed, not by the power nor through the merits of the Israelites, but through the power and goodness of God; see (Psalms 44:3) .