He shall drink of the brook in the way - The design here seems to be to represent the Messiah as a victorious king and conqueror pursuing his enemies. In the previous verse the psalmist had represented him under the image of one engaged in battle, and slaying his enemies with a great slaughter. He here represents him as pursuing those who should escape from the battle, and as pursuing them without fainting or exhaustion. He is like one who finds abundant springs and streams of water in his journeyings; who refreshes himself at those fountains and streams; who, therefore, is not faint and weary. He pursues his foes vigorously and with success.
Therefore shall he lift up the head - Therefore shall he triumph, or be successful. The head falls when we are faint and exhausted, when we are disappointed and are ashamed, when we are conscious of guilt. It is lifted up in conscious rectitude, in success and triumph, in the exuberance of hope. The idea here is, that the Messiah would be triumphant. He would achieve the victory over all his foes; he would pursue, without exhaustion, his flying enemies, and he would return from the conquest joyous, exulting, triumphant. All this is under the image of a victorious hero; all this will be accomplished in the conquest of the world by the Gospel; in the subduing of the foes of God; in the final scene when the Redeemer shall deliver up the kingdom to God. 1 Corinthians 15:24-28.