וְֽאַל־תַּצֵּ֬ל מִפִּ֣י דְבַר־אֱמֶ֣ת עַד־מְאֹ֑ד כִּ֖י לְמִשְׁפָּטֶ֣ךָ יִחָֽלְתִּי׃
און זאָלסט ניט אָפּרײַסן אין גאַנצן פֿון מײַן מױל דאָס װאָרט פֿון אמת, װאָרום אױף דײַנע משפּטים האָב איך געהאַרט.
Rashi
And do not take...from my mouth a word of truth Heb. תצל. Do not separate from my mouth a word of truth, as (Gen. 31:9): “And God separated (ויצל) your father’s property and gave it to me.” I found this.
Rashi
utterly...a word of truth in all my instructions [regarding ritual law] and in all my legal decisions, that I should not stumble over them.