Albert Barnes Commentary Psalms 46:2

"Therefore will we not fear, though the earth do change, And though the mountains be shaken into the heart of the seas;" — Psalms 46:2 (ASV)

Therefore will not we fear – Our confidence in God will be unshaken and enduring. Having Him for our refuge and strength (Psalms 46:1), we can have nothing to fear. .

Though the earth be removed – literally, “in the changing of the earth;” that is, though the earth should be changed. This may mean either that the earth should change its place or its very structure in these convulsions, or that it should perish altogether. . The idea is that they would not be afraid, even if the convulsions then occurring in the world should continue and extend so far as to destroy the very earth itself. God would remain their friend and protector, and they would have nothing to fear.

And though the mountains be carried into the midst of the sea – Margin, as in Hebrew, “into the heart of the seas.” This may be understood literally, implying that they would not be afraid even if the mountains, the most fixed and firm things of earth, should be uprooted and sunk in the ocean—which implies that nothing earthly was stable. Alternatively, the mountains here may be referred to as emblems of what seemed to be most settled and established on earth: the kingdoms of the world.

The idea is that in any convulsion, any change, or any threatened danger, they would place confidence in God, who ruled over all and who could not change. It will be readily seen that this entire description of trust and confidence in God is applicable to the time of Hezekiah and to the feelings he manifested when the land was invaded by the hosts of Sennacherib, and when wars and commotions were occurring among the kingdoms of the earth. (See the introduction to the psalm).

It was also eminently suited to console the mind in the circumstances to which Luther so often applied the psalm—the agitations, convulsions, wars, and dangers in Europe during the time of the Reformation. It is suited to any time of trouble, when commotions and revolutions are occurring in the earth, and when everything sacred, true, and valuable seems to be in danger.