וַיְהִ֣י אַבְרָ֔ם בֶּן־תִּשְׁעִ֥ים שָׁנָ֖ה וְתֵ֣שַׁע שָׁנִ֑ים וַיֵּרָ֨א יְהוָ֜ה אֶל־אַבְרָ֗ם וַיֹּ֤אמֶר אֵלָיו֙ אֲנִי־אֵ֣ל שַׁדַּ֔י הִתְהַלֵּ֥ךְ לְפָנַ֖י וֶהְיֵ֥ה תָמִֽים׃
And when Abram was ninety years old and nine, the LORD appeared to Abram, and said unto him: ‘I am God Almighty; walk before Me, and be thou wholehearted.
Read halakhic rulings (Jewish law) on Genesis 17:1: and classical halakhic sources.