Chasidut zu Jeschijahu 63:16

Another way of interpreting the peculiarity of the verse ‎citing specifically “the G’d of Yitzchok his father,” addresses the ‎statement of the Talmud on the same folio, when it quotes a ‎verse in Isaiah 63,16 ‎כי אתה אבינו כי אברהם לא ידענו וישראל לא יכירנו ‏אתה ה' אבינו גואלנו מעולם שמך‎, “for You are our Father, for though ‎Avraham did not know us and Israel has not recognized us, You O ‎Lord, are our Father.” The Talmud explains the background to ‎this perplexing verse. It states that in the future, when G’d would ‎say to Avraham: “your children have sinned against Me,” ‎Avraham’s response was “let them atone by having to die for the ‎sanctification of Your name.” The Talmud quotes Yaakov at that ‎time as adopting a similar attitude. Only Yitzchok is quoted as ‎challenging G’d, describing the Jews as the children of Avraham ‎and Yaakov and himself, without at the same time describing ‎them also as His children. When Yaakov presented his offerings ‎at Beer Sheva in honour of the G’d of Yitzchok, he meant to ‎remind G’d of this concern of his father Yitzchok for his children ‎even if at the time they were sinful.‎