John Calvin Commentary Isaiah 25:4

"For thou hast been a stronghold to the poor, a stronghold to the needy in his distress, a refuge from the storm, a shade from the heat, when the blast of the terrible ones is as a storm against the wall." — Isaiah 25:4 (ASV)

For thou hast been a strength to the poor. Therefore, we see the fruit of conversion: namely, that the Lord raises us from the dead and brings us, as it were, out of the grave, stretching out his hand to us from heaven to rescue us even from hell. This is our first access to him, for it is only in our poverty that he finds the means of exercising his kindness. Therefore, in turn, it is necessary for us to be poor and needy, so that we may obtain assistance from him; and we must lay aside all reliance and confidence in ourselves before he displays his power on our behalf. This is the reason why he visits us with chastisements and with the cross, by which he trains us, so that we may be able to receive his assistance and grace.

A refuge from the storm, a shadow from the heat. It is not without good reason that Isaiah adorns this description with these comparisons, for numerous and diversified temptations arise, and, in order to bear them courageously, it is necessary for the weak minds of men to be strengthened and fortified. For this reason he says that God will be a strength to the poor, a refuge from the storms, and a shadow from the heat; because, whatever may be the nature of the dangers and assaults that threaten them, the Lord will protect his people against them and will supply them with every kind of armor.

The breath of the strong or of the violent ones. In this passage, as in many others (Genesis 8:1; Exodus 15:10; 1 Kings 19:11), רוח (rūăch) signifies “the blowing of the wind,” and denotes the tremendous violence with which wicked men are hurried along against the children of God; for not only do they breathe out threatenings and terrors (Acts 9:1), but they appear to vomit out fire itself.

A storm or flood against the wall. This has the same meaning as the former statement. By this figure, he means that wicked men, when they obtain freedom to do mischief, rush on with such violence that they throw down everything in their way. This is because overthrowing and destroying walls is a more severe action than water merely flowing over the fields.