Matthew Henry Commentary Psalms 68:29-31

"Because of thy temple at Jerusalem Kings shall bring presents unto thee. Rebuke the wild beast of the reeds, The multitude of the bulls, with the calves of the peoples, Trampling under foot the pieces of silver: He hath scattered the peoples that delight in war. Princes shall come out of Egypt; Ethiopia shall haste to stretch out her hands unto God." — Psalms 68:29-31 (ASV)

A powerful invitation is given to those who are outside, to join the church. Some will submit from fear; overcome by their consciences and the restraints of Providence, they are brought to make peace with the church. Others will submit willingly (verses 29 and 31). There is such beauty and benefit in the service of God, and in the gospel of Christ which went forth from Jerusalem, that it is enough to invite sinners from all nations.