Tosefta for Leviticus 21:11

וְעַ֛ל כָּל־נַפְשֹׁ֥ת מֵ֖ת לֹ֣א יָבֹ֑א לְאָבִ֥יו וּלְאִמּ֖וֹ לֹ֥א יִטַּמָּֽא׃

neither shall he go in to any dead body, nor defile himself for his father, or for his mother;