Psalm 20:7 (ESV)

            7       Some trust in chariots and some in horses,

      but we trust in the name of the LORD our God.

What is the trust which is commended here?  To say that I trust in the name of the Lord when I am not facing any trouble allows me the appearance of faithfulness without the cost. There is no actual trust in such a situation.

At the other end, one who is in an solvable problem for which there is viable response, to say I trust the Lord means more I hope the Lord will act. There is some actual trust here, but it is a trust without other option. I trust in the Lord, because there is nothing else I can do.

There is a third situation where I could act, and in fact will act, but my trust is not in my own conduct but in God.

Then looking to the commentators:

4. Weak man cannot choose but have some confidence, without himself, in case of apparent difficulties; and natural men do look first to some earthly thing wherein they confide: some trust in chariots, and some in horses, some in one creature, some in another. 5. The believer must quit his confidence in these things, whether he have them, or want them, and must rely on what God hath promised in his word to do unto us: but we will remember the name of the Lord our God.

Dickson, David. A Brief Explication of the Psalms. John Dow; Waugh and Innes; R. Ogle; James Darling; Richard Baynes, 1834, p. 100.

Cassiodorus takes the passage in a very different way. He speaks of the sorts of triumphs one could enjoy with chariot and horse, then concludes:

But the psalmist leaves such things to worldly men, and maintains that he has been exalted in the Lord’s name. It is not chariots or the horse that exalt, though they are seen to glorify with distinctions in this world, but the Lord’s name which in the end leads to eternal rewards.

Cassiodorus. Cassiodorus: Explanation of the Psalms. Edited by Walter J. Burghardt and Thomas Comerford Lawler, Translated by P. G. Walsh, 51st ed., vol. I, Paulist Press, 1990, p. 207.

Some trust in chariots. I do not restrict this to the enemies of Israel, as is done by other interpreters. I am rather inclined to think that there is here a comparison between the people of God and all the rest of the world. We see how natural it is to almost all men to be the more courageous and confident the more they possess of riches, power, and military forces. The people of God, therefore, here protest that they do not place their hope, as is the usual way with men, in their military forces and warlike apparatus, but only in the aid of God. As the Holy Spirit here sets the assistance of God in opposition to human strength, it ought to be particularly noticed, that whenever our minds come to be occupied by carnal confidence, they fall at the same time into a forgetfulness of God. It is impossible for him, who promises himself victory by confiding in his own strength, to have his eyes turned towards God. The inspired writer, therefore, uses the word remember, to show, that when the saints betake themselves to God, they must cast off every thing which would hinder them from placing an exclusive trust in him

Calvin, John, and James Anderson. Commentary on the Book of Psalms. Logos Bible Software, 2010, p. 340.

LUTHER: God must help and advise; our plans and actions are otherwise of no value.—OSIANDER: Great, exalted titles do not make a king invincible, but God’s help, which is gained by the prayer of faith. The victory is a gift of God, and is not accomplished by great preparation or a great host

Lange, John Peter, et al. A Commentary on the Holy Scriptures: Psalms. Logos Bible Software, 2008, p. 160.

A collect based on the Psalm:

Hear us, O LORD, we beseech Thee, in the day of trouble, and defend us from all evils, that risen, and standing upright, when our enemies are fallen, we may ever rejoice in Thee, our LORD and GOD.

Neale, J. M. A Commentary on the Psalms from Primitive and Mediæval Writers: Psalm 1 to Psalm 38. Second Edition, vol. 1, Joseph Masters; Pott and Amery, 1869, p. 269.