| Barnes' Notes on the Bible Through God we shall do ... - This also is taken from Psalm 60:12, without change. Thus the psalm, though made up of parts of two separate psalms, is complete and continuous in itself. There is no break or discrepancy in the current of thought, but the unity is as perfect as though it had been an original composition. It is to be remarked, also, that though in the original psalms the parts which are used here have a different connection, and are separately complete there, yet as employed here, they seem to be exactly suited to the new use which is made of the language; and though the original "reasons" for the use of the language do not appear here, yet there is a sufficient reason for that language apparent in the psalm as rearranged. To an Israelite, also, there might be a new interest in the use of the language in the fact that words with which he was familiar, as employed for other purposes, "could" be thus combined, and made applicable to a new occasion in the national history.
Clarke's Commentary on the BibleThrough God we shall do valiantly - From him we derive our courage, from him our strength, and by him our success. [For the Analysis, see the Psalm 57:1-11 (note) and Psalm 60:1-12 (note). Also see introduction to Psalm 108:1-13 (note)]
The Treasury of David13 Through God we shall do valiantly, for he it is that shall tread down our enemies. Psalm 108:13 God's help shall inspire us to help ourselves. Faith is neither a coward nor a sluggard she knows that God is with her, and therefore she does valiantly; she knows that he will tread down her enemies, and therefore she arises to tread them down in his name. Where praise and prayer have preceded the battle, we may expect to see heroic deeds and decisive victories. "Through God" is our secret support; from that source we draw all our courage, wisdom, and strength. "We shall do valiantly." This is the public outflow from that secret source our inward and spiritual faith proves itself by outward and valorous deeds. "He shall tread down our enemies." They shall fall before him, and as they lie prostrate he shall march over them, and all the hosts of his people with him. This is a prophecy. It was fulfilled to David, but it remains true to the Son of David and all who are on his side. The church shall yet arouse herself to praise her God with all her heart, and then with songs and hosannas she will advance to the great battle; her foes shall be overthrown and utterly crushed by the power of her God, and the Lord's glory shall be above all the earth. Send it in our time, we beseech thee, O Lord.
Geneva Study BibleThrough God we shall do valiantly: for he it is that shall tread down our enemies.
Matthew Henry's Concise Commentary108:1-13 We may usefully select passages from different psalms, as here, Ps 57; 60, to help our devotions, and enliven our gratitude. When the heart is firm in faith and love, the tongue, being employed in grateful praises, is our glory. Every gift of the Lord honours and profits the possessor, as it is employed in God's service and to his glory. Believers may pray with assured faith and hope, for all the blessings of salvation; which are secured to them by the faithful promise and covenant of God. Then let them expect from him help in every trouble, and victory in every conflict. Whatever we do, whatever we gain, God must have all the glory. Lord, visit all our souls with this salvation, with this favour which thou bearest to thy chosen people. | 
