Commentary on the Bible, by Adam Clarke, [1831], at sacred-texts.com
A prayer for the king in his enterprises, that his prayers may be heard, his offerings accepted, and his wishes fulfilled, Psa 20:1-4. Confidence of victory expressed, Psa 20:5, Psa 20:6. Vain hopes exposed; and supplication made for the king, Psa 20:7-9.
It is most likely that this Psalm was penned on the occasion of David's going to war, and most probably with the Ammonites and Syrians, who came with great numbers of horses and chariots to fight with him. See Sa2 10:6-8; Ch1 19:7. It is one of the Dialogue Psalms, and appears to be thus divided: Previously to his undertaking the war, David comes to the tabernacle to offer sacrifice. This being done, the people, in the king's behalf, offer up their prayers; these are included in the three first verses: the fourth was probably spoken by the high priest; the fifth, by David and his attendants; the last clause, by the high priest; the sixth, by the high priest, after the victim was consumed; the seventh and eighth, by David and his men; and the ninth, as a chorus by all the congregation.
The Lord hear thee - David had already offered the sacrifice and prayed. The people implore God to succor him in the day of trouble; of both personal and national danger.
The name of the God of Jacob - This refers to Jacob's wrestling with the Angel; Gen 32:24 (note), etc. And who was this Angel? Evidently none other than the Angel of the Covenant, the Lord Jesus, in whom was the name of God, the fullness of the Godhead bodily. He was the God of Jacob, who blessed Jacob, and gave him a new name and a new nature. See the notes on the above place in Genesis.
Send thee help from the sanctuary - This was the place where God recorded his name; the place where he was to be sought, and the place where he manifested himself. He dwelt between the cherubim over the mercyseat. He is now in Christ, reconciling the world to himself. This is the true sanctuary where God must be sought.
Strengthen thee out of Zion - The temple or tabernacle where his prayers and sacrifices were to be offered.
Remember all thy offerings - The minchah, which is here mentioned, was a gratitude-offering. It is rarely used to signify a bloody sacrifice.
Burnt sacrifice - The olah here mentioned was a bloody sacrifice. The blood of the victim was spilt at the altar, and the flesh consumed. One of these offerings implied a consciousness of sin in the offerer; and this sacrifice he brought as an atonement: the other implied a sense of mercies already received, and was offered in the way of gratitude.
David presents himself before the Lord with offerings of both kinds.
This prayer of the people is concluded with Selah, which we have taken up in the general sense of so be it. Hear and answer. It will and must be so, etc.
Grant thee according to thine own heart - May God give thee whatsoever thou art setting thy heart upon, and accomplish all thy desires! This was probably the prayer of the high priest.
We will rejoice in thy salvation - We expect help from thee alone; it is in thy cause we engage; and to thee, as our war is a just one, we consecrate our banners, inscribed with thy name. It is said that the Maccabees had their name from the inscription on their banners; which was taken from Exo 15:11, מי כמכה באלם יהוה mi camochah baelim Yehovah, "Who is like unto thee, O Lord, among the gods?" The word being formed from the initial letters מ M, כ C, ב B, י I, מכבי Ma Ca B I, whence Maccabeus and Maccabees.
The words of this verse were spoken by David and his officers; immediately after which I suppose the high priest to have added, The Lord fulfill all thy petitions!
Now know I that the Lord saveth his anointed - These are probably the words of the priest after the victim had been consumed; and those signs had accompanied the offering, which were proofs of God's acceptance of the sacrifice; and, consequently, that the campaign would have a successful issue. David is God's anointed; therefore, he is under his especial care. He will hear him. David must continue to pray, and to depend on God; else he cannot expect continual salvation. David has vast multitudes of enemies against him; he, therefore, requires supernatural help. Because of this, God will hear him with the saving strength of his right hand.
The Hand of God is his power, the Right hand, his almighty power; the Strength of his right hand, his almighty power in action; the Saving strength of his right hand, the miraculous effects wrought by his almighty power brought into action. This is what David was to expect; and it was the prospect of this that caused him and his officers to exult as they do in the following verse.
Some trust in chariots - The words of the original are short and emphatic: These in chariots; and these in horses; but we will record in the name of Jehovah our God. Or, as the Septuagint, μεγαλυνθησομεθα, "we shall be magnified." Or, as the Vulgate, invocabimus, "we shall invoke the name of the Lord." This and the following verse I suppose to be the words of David and his officers. And the mention of chariots and horses makes it likely that the war with the Ammonites and Syrians is that to which reference is made here; for they came against him with vast multitudes of horsemen and chariots. See Sa2 10:6-8. According to the law, David could neither have chariots nor horses; and those who came against him with cavalry must have a very great advantage; but he saw that Jehovah his God was more than a match for all his foes, and in him he trusts with implicit confidence.
They are brought down and fallen - They were so confident of victory that they looked upon it as already gained. They who trusted in their horses and chariots are bowed down, and prostrated on the earth: they are all overthrown.
But we are risen - We who have trusted in the name of Jehovah are raised up from all despondency; and we stand upright - we shall conquer, and go on to conquer.
Save, Lord - This verse was spoken by all the congregation, and was the chorus and conclusion of the piece.
The verse may be read, Lord, save the king! He will hear as in the day of our calling. The Vulgate, Septuagint, Ethiopic, Arabic, Anglo-Saxon, read the verse thus: Lord, save the king! and hear us whensoever we shall call upon thee. The Syriac reads differently: The Lord will save us: and our king will hear us in the day in which we shall call upon him. This refers all to God: while the others refer the latter clause to David. Lord, save David; and David will save us. "If thou preservest him, he will be thy minister for good to us." This appears to be the easiest sense of the place, and harmonizes with all the rest.