David
Psalm 135:8ESV·traditional attribution

He it was who struck down the firstborn of Egypt, both of man and of beast;

John Calvin Reformed @genevareformer

Psalm 135 An exhortation to praise God, both for his goodness specially shown to his chosen people, and for his power and glory apparent in the world at large. A contrast is drawn between idols, which had but a vain show of divinity, and the God of Israel, who had established his claim to be considered the only true God by clear and indubitable proofs...

Commenting on Psalm 135:1-21

C.H. Spurgeon Reformed Baptist @princeofpreachers

Who smote the firstborn of Egypt, both of man and beast. Herein the Lord is to be praised; for this deadly smiting was an act of justice against Egypt, and of love to Israel. But what a blow it was! All the firstborn slain in a moment! How it must have horrified the nation, and cowed the boldest enemies of Israel!

Matthew Henry Presbyterian @wholebiblehenry

The psalmist had suggested to us the goodness of God, as the proper matter of our cheerful praises; here he suggests to us the greatness of God as the proper matter of our awful praises; and on this he is most copious, because this we are less forward to consider. I.

Commenting on Psalm 135:5-14