וַיִּשְׁכַּ֥ב אָסָ֖א עִם־אֲבֹתָ֑יו וַיָּ֕מָת בִּשְׁנַ֛ת אַרְבָּעִ֥ים וְאַחַ֖ת לְמָלְכֽוֹ׃
And Asa slept with his fathers, and died in the one and fortieth year of his reign.
Read kabbalistic (mystical) interpretation of II Chronicles 16:13: and classical mystical sources.