וַיֶּחֱלֶ֣א אָסָ֡א בִּשְׁנַת֩ שְׁלוֹשִׁ֨ים וָתֵ֤שַׁע לְמַלְכוּתוֹ֙ בְּרַגְלָ֔יו עַד־לְמַ֖עְלָה חָלְי֑וֹ וְגַם־בְּחָלְיוֹ֙ לֹא־דָרַ֣שׁ אֶת־יְהוָ֔ה כִּ֖י בָּרֹפְאִֽים׃
And in the thirty and ninth year of his reign Asa was diseased in his feet; his disease was exceeding great; yet in his disease he sought not to the LORD, but to the physicians.
Read midrashic interpretation of II Chronicles 16:12: and classical rabbinic exegesis.