וַיֹּ֤אמֶר יִצְחָק֙ אֶֽל־יַעֲקֹ֔ב גְּשָׁה־נָּ֥א וַאֲמֻֽשְׁךָ֖ בְּנִ֑י הַֽאַתָּ֥ה זֶ֛ה בְּנִ֥י עֵשָׂ֖ו אִם־לֹֽא׃
And Isaac said unto Jacob: ‘Come near, I pray thee, that I may feel thee, my son, whether thou be my very son Esau or not.’
Read halakhic rulings (Jewish law) on Genesis 27:21: and classical halakhic sources.