Psalms 149:8

To bind their kings with chains - To make them prisoners and captives. This is but carrying out the idea in the previous verses, of inflicting punishment upon them for the wrongs which they had done to the people of God. There is no evidence that this refers to a spiritual conquest, or to a spiritual subjection of those nations to the true religion. The whole idea is in accordance with what is so often expressed in the Psalms - that of inflicting just punishment on the wicked. See the General Introduction, Section 6.

And their nobles with fetters of iron - To make them prisoners. That is, to subdue them. Captives in war, even those of elevated rank, were often led in chains to grace the triumph of conquerors.