Charles H. Spurgeon on Psalms 78:23

Opened the doors of heaven. This is a metaphor taken from a granary, from which corn is brought; and by opening the doors is signified, that the manna fell very plentifully. Compare Ge 7:11. Thomas Fenton.

Verse 24-25. Manna. The prophet celebrates this miracle, first, because of the unusual place whence the manna was sent. For he did not produce fruits from the earth wherewith to feed them, but rained down this food from the clouds, and from the depths of the skies. Secondly, because of the facility of the distribution. By the command of God alone, without any labour of men, yea, while they slept, this food was prepared. Therefore is it said, He gave, etc. Thirdly, he celebrates its great abundance which sufficed to supply so great a multitude. Fourthly, the excellence of the food. He calls it the food of the excellent or the strong, such as was not pleasant merely to the common multitude, but to the princes also, and to the heroes, for it was the food of the mighty ones. Mollerus.