Since he was a prophet and knew that God had pledged His word that one of his [i.e., David's] descendants would sit on his throne [as king];

Now David is not the one who ascended into heaven for he [spoke of Jesus when he] said [Psa. 110:1], 'The Lord [i.e., God] said to my [i.e., David's] Lord [i.e., Jesus], sit at my right side

That Tent was bequeathed to the next generation of our forefathers. Under Joshua they brought it with them when they were taking possession of the land of the Gentile nations, whom God drove out before them. So it continued till David's time.

"It is from among David's descendants that God, in fulfilment of His promise, has raised up a Saviour for Israel, even Jesus.

After these things I will return
and rebuild David’s fallen tent.
I will rebuild its ruins
and set it up again,