Commentary on the Bible, by Adam Clarke, , at sacred-texts.com
The psalmist prays for the enlargement of God's kingdom, Psa 67:1, Psa 67:2; calls upon all nations to serve him, because he judges and governs righteously, Psa 67:3-5; promises prosperity to the faithful and obedient, Psa 67:6, Psa 67:7.
The title here is the same with that of Psa 4:1-8 (note), where see the notes. It is supposed to have been written at the return from the Babylonish captivity, and to foretell the conversion of the Gentiles to the Christian religion. The prayer for their salvation is very energetic.
God be merciful unto us - Show the Jewish people thy mercy, bless them in their bodies and souls and give a full evidence of thy approbation. This is nearly the same form of blessing as that used Num 6:25 (note), where see the notes.
That thy way may be known - That thy will, thy gracious designs towards the children of men, thy way of reconciling them to thyself, of justifying the ungodly, and sanctifying the unholy, may be known to all the nations upon the earth! God's way is God's religion; what he walks in before men; and in which men must walk before him. A man's religion is his way of worshipping God, and going to heaven. The whole Gospel is called this way, Act 19:9.
Thy saving health - ישועתך yeshuathecha, "thy salvation." The great work which is performed in God's way, in destroying the power, pardoning the guilt, cleansing from the infection, of all sin; and filling the soul with holiness, with the mind that was in Christ. Let all nations - the whole Gentile world, know that way, and this salvation!
Let the people praise thee - When this is done, the people - the Gentiles, will praise thee; all will give thanks to God for his unspeakable gift.
Glad and sing for joy - They shall be made happy in thy salvation. Even their political state shall be greatly meliorated; for God will be acknowledged the supreme Judge; their laws shall be founded on his word; and the nations of the earth shall be governed according to judgment, justice, and equity.
Selah - This is true. There are innumerable facts to confirm it. All the nations who have received the Gospel of Christ have been benefited politically, as well as spiritually, by it.
Let the people praise thee - Seeing the abundance of the blessings which the Gentiles were to receive, he calls again and again upon them to magnify God for such mercies.
The earth yield her increase - As the ground was cursed for the sin of man, and the curse was to be removed by Jesus Christ, the fertility of the ground should be influenced by the preaching of the Gospel; for as the people's minds would become enlightened by the truth, they would, in consequence, become capable of making the most beneficial discoveries in arts and sciences, and there should be an especial blessing on the toil of the pious husbandman. Whenever true religion prevails, every thing partakes of its beneficent influence.
God shall bless us - He shall ever be speaking good to us, and ever showering down good things upon us.
The last clause of the sixth verse should be joined to the seventh, as it is in several of the Versions, and should be in all. Many of the fathers, and several commentators, have thought that there is a reference to the Holy Trinity in the triple repetition of the word God: "God, our God, shall bless us; God shall bless us;" thus paraphrased in the old Psalter: "Blis us God the Fader: and our God the sone: and blis us and multipli us God the Hali Gast; that swa drede him God, all the endis of erth; for he wil comme to deme rightwysly that unrightwysly was demed. He that kan drede him, he eesses noght to lufe him."
When or by whom this Psalm was written cannot be ascertained. It seems to be simply a prophecy concerning the calling of the Gentiles, the preaching of the apostles, and the diffusion and influence of Christianity in the world. It is a fine piece of devotion; and it would be nearly impossible to read or repeat it with a cold and unaffected heart.