John Trapp on Psalms 78:9

Verſ. 9. The children of Ephraim being armed, &c.] This the Rabbines interpret of eight thouſand Ephraimites, who would needs break priſon, as it were, out of Egypt (before the time that God had ſet for their deliverance thence) and ſeize upon Paleſtina the promiſed Land; but with evill ſucceſſe; for they were ſlain by the men of Gath, to the great grief of their Father Ephraim, 1 Chron. 7.21, 22, 23. and to the increaſe of their ſervitude in Egypt, Exod. 1. This is hiſtoria Caballica. See R. Solomon on thoſe words, Exod. 15.14. the people ſhall hear and be afraid; ſorrow ſhall take hold on the inhabitants of Paleſtina, who remembring what a ſlaughter they once made of theſe Ephraimites, ſhall fear the juſt revenge of that cruelty. Others interpret this text by Judg. 1.29. and ſome by 2 King. 17. with Hoſ. 10.6, 7, 8, &c. but this to mee ſeemeth likelieſt. Theſe are ancient things, and of ſuch the Pſalmiſt promiſeth to treat, verſ. 2, 3.

Being armed and carrying bows] Truſting to their own ſtrength, and warlike preparations; and chuſing rather to be counted temerarious than timorous.

Turned back in the day of battel] Carnal confidence ſeldome comes home, otherwiſe than weeping.