Acts 15:16-17

Ac 15:16 After this I will return, and will build again the tabernacle of David, which is fallen down; and I will build again the ruins thereof, and I will set it up:

Ac 15:17 That the residue of men might seek after the Lord, and all the Gentiles, upon whom my name is called, saith the Lord, who doeth all these things.

Why does James cite Amos 9?

Am 9:11 ¶ In that day will I raise up the tabernacle of David that is fallen, and close up the breaches thereof; and I will raise up his ruins, and I will build it as in the days of old:

Am 9:12 That they may possess the remnant of Edom, and of all the heathen, which are called by my name, saith the LORD that doeth this.