'Embittered' in the Bible

but the unbelieving Jews [who rejected Jesus as Messiah] stirred up and embittered the minds of the Gentiles against the believers.

while it is said,“Today [while there is still opportunity] if you hear His voice,Do not harden your heart, as when they provoked Me [in the rebellion in the desert at Meribah].”

So I took the little book from the angel’s hand and ate it, and in my mouth it was as sweet as honey; but once I had swallowed it, my stomach was bitter.