וּמִבֶּן֙ חֲמִשִּׁ֣ים שָׁנָ֔ה יָשׁ֖וּב מִצְּבָ֣א הָעֲבֹדָ֑ה וְלֹ֥א יַעֲבֹ֖ד עֽוֹד׃
and from the age of fifty years they shall return from the service of the work, and shall serve no more;
Targum Jonathan on Numbers
and from fifty years of age he shall return from the band of the service, and serve no more.