en_tn/1sa/14/12.md

we will show you something

This is an idiom that means "we will teach you a lesson." (See: rc://en/ta/man/jit/figs-idiom)

has given them into the hand of Israel

Here "hand" refers to power to defeat the Philistines. Alternate translation: "will enable Israel to defeat them" (See: rc://en/ta/man/jit/figs-metonymy)