Maschil is a musical reference. As for the sons of Korah, descendants of the rebel Korah whose children, spared by grace, took a conspicuous part in the Temple worship of song. They were only receivers not writers of the Psalm. Probably the Levites who were with David (2 Sam 15:24) include Korah's sons.
We see here the hart in the wilderness panting for the water brooks which it has not found. It stands on some bank hangs over the brook, the water is not reached. Such is the Psalmist's state of soul: "O that I might see the face of God!" is the force of verse 2; and verse 4 is the soul responding to itself saying in remembrance of past joys now withheld: "I will think on this and pour out my soul within me."
The Septuagint has translated this very nearly in the words used in Matt 26:38 and John 12:27.
"My soul, why are you very sorrowful?"
"Why are you troubled within me?"
Our Lord, as well as every troubled and sorrowful one of his people, could use this Psalm, when, as the true David, he was driven out, not by a son, but by his Father for our sakes - driven farther from heaven than Hermon or Jordan, or "the Little Hill" are from Zion and the Tabernacle, hearing deeper floods calling to one another, and mustering their waters, as at the deluge the cataracts dashed upon the ark from above, while bursting fountains heaved it up from below.
Still, He knew the issue: "For the joy set before Him he endured the cross."
He could sing in the gloom, "I shall yet praise him, the salvation of my face, and my God!" The marginal reading is, "His presence is salvation;" but verse 11 is against this.
The meaning is,
I shall praise Him as He who shall change my marred form, and give me beauty; who shall change my humiliation into exaltation; who shall in my case, and then in the case of all my people, exchange the wilderness and its parched sands for the kingdom and its rivers of pleasure.The secret pang of Christ, arising from reproach and scorn was that which he felt when they cast suspicion on the love and faithfulness of his Father (v10), "Where is your God?"
In proportion as sanctification advances, his members feel this, too, forgetting their own glory, and intent upon his.
In the primary use of the Psalm, this taunt would be felt by David when his enemies insinuated that though God had anointed him king, yet He could not bring him to his kingdom: or even if "the sons of Korah" wrote this Psalm (as Hengstenberg thinks), there would be the same feeling in them in regard to this taunt flung at that devoted leader, whose cause they espoused, coming to him at Ziklag. (1 Chron 12:6)
But the Holy Spirit founded on these circumstances a song of Zion, which was meant for Zion's King, and all his princes in their passage to the throne and kingdom. The Lord Jesus might especially call it to mind, and sing it with his disciples on that remarkable day when, at Caesarea Phillippi (Matt 16:13), he asked what men were saying of him? On that day, Hermon was in sight, and Jordan's double-fountain close beside him, and some "Little Hill" near them, some "Mizar," that, by contrast, called up to mind the Hills of Zion.
On that day, it may be, the Head of the Church made special use of this Psalm, and embalmed it in the hearts of his disciples, who would never afterwards fail to sing it (even as we do), with double refreshment in the thought that it had comforted the Master, expressing, as it does The Righteous One in his weariness looking up to the Father for refreshment.