John Wesley on Psalms 87:7

Singers - There shall be great rejoicing and praising God, both with vocal and instrumental musick, for this glorious work of the conversion of the Gentiles. He describe's evangelical worship, by legal phrases and customs, as the prophets frequently do. In thee - In Zion or the church. These words may be here added as the burden of the song, which these singers are supposed to have sung, in the name of all the people of God. All our desires and delights are in thee, all the springs of mercy, grace, and glory, flow to us only in and thro' thee.