I Samuel 18:29 Midrash

וַיֹּ֣אסֶף שָׁא֗וּל לֵרֹ֛א מִפְּנֵ֥י דָוִ֖ד ע֑וֹד וַיְהִ֥י שָׁא֛וּל אֹיֵ֥ב אֶת־דָּוִ֖ד כָּל־הַיָּמִֽים׃ (ס)

And Saul was yet the more afraid of David; and Saul was David’s enemy continually.

Read midrashic interpretation of I Samuel 18:29: and classical rabbinic exegesis.