Reference for Psalms 50:20

תֵּ֭שֵׁב בְּאָחִ֣יךָ תְדַבֵּ֑ר בְּבֶֽן־אִ֝מְּךָ֗ תִּתֶּן־דֹּֽפִי׃

Thou sittest and speakest against thy brother; Thou slanderest thine own mother's son.