כִּ֚י לֹ֣א הַרְבֵּ֔ה יִזְכֹּ֖ר אֶת־יְמֵ֣י חַיָּ֑יו כִּ֧י הָאֱלֹהִ֛ים מַעֲנֶ֖ה בְּשִׂמְחַ֥ת לִבּֽוֹ׃
For let him remember the days of his life that they are not many; for God answereth him in the joy of his heart.
Read kabbalistic (mystical) interpretation of Ecclesiastes 5:19: and classical mystical sources.