John Calvin Commentary Psalms 104:27

"These wait all for thee, That thou mayest give them their food in due season." — Psalms 104:27 (ASV)

All these wait upon you. The prophet here again describes God as acting as the master of a household and a foster-father towards all kinds of living creatures, by liberally providing for them. He had said before that God made food to grow on the mountains for the support of cattle, and that sustenance is provided to even the lions by God's own hand, although they live on prey.

He now amplifies this wonder of divine beneficence with an additional circumstance. While the different species of living creatures are almost innumerable, and the number in each species is so great, still every one of them needs daily food. The meaning then of the expression, All things wait upon you, is that they could not continue to exist even for a few days unless God supplied their daily need and nourished each of them individually.

Thus, we see why there is such a great diversity of fruits; for God assigns and appoints to each species of living creatures the food that is suitable and proper for them. The brute beasts are not indeed endowed with reason and judgment to seek the supply of their needs from God, but stooping towards the earth, they seek to fill themselves with food; still, the prophet speaks appropriately when he represents them as waiting upon God, for their hunger must be relieved by his bounty, otherwise they would soon die.

Nor is the specification of the season when God provides them with food unnecessary, since God stores up for them, so that they may have sustenance throughout the entire year. As the earth in winter withholds its bounty, what would become of them if he did not provide them with food for a long time?

The miracle, then, is all the greater because God, by making the earth fruitful at appointed seasons, in this way extends his blessing to the rest of the year, which threatens us with hunger and famine. How wretched would we be when the earth in winter withholds its riches, if our hearts were not cheered with the hope of a new harvest? In this sense, the Psalmist appropriately affirms that God opens his hand.

If wheat were to grow daily, God's providence would not be so evident. But when the earth becomes barren, it is as if God shut his hand. Therefore, it follows that when he makes it fruitful, he, so to speak, stretches out his hand from heaven to give us food. Now if he supplies wild and brute beasts with sustenance at the proper time, by which they are fully fed, his blessing will doubtless be to us an inexhaustible source of plenty, provided we ourselves do not, by our unbelief, hinder it from flowing to us.