John Wesley on Psalms 87:4

Rahab - Egypt, so called, either from its pride or natural strength. Babylon - Under these two and Philistia, the constant enemies of Israel, he seems to understand all the enemies of the church of God, who shall now be not only reconciled but united to them. Arabia - The nations on every side of them, for Tyre was on the north, Arabia on the South; those nearest to them, and those more remote from them.