Albert Barnes Commentary Psalms 78:51

"And smote all the first-born in Egypt, The chief of their strength in the tents of Ham." — Psalms 78:51 (ASV)

And smote all the firstborn in Egypt — See Exodus 11:4-5; Exodus 12:29–30.

The chief of their strength — Those on whom they relied; their firstborn; their pride; their glory; their heirs. Compare Genesis 49:3.

In the tabernacles of Ham — The tents; the dwelling-places of Ham; that is, of Egypt. Compare Genesis 10:6; Psalms 105:23, Psalms 105:27; Psalms 106:22.