Isaiah 51:1-2 commands us to "look unto Abraham" as our father, and John the Baptist chides those who were looking to Abraham but in such a way that condemned them (Matt 3:9).
Jesus made clear that there were those who claimed to have Abraham as their father in fact did not (John 8:39ff). And Paul told some that the way they looked to Abraham actually made them sons of Hagar (Gal 4:24).
Which is it? Are we to look to Abraham or not?
"To the unconverted heart it sure looks (as though God is trifling with us). To the converted heart, the distance between looking to Abraham and looking to Abraham is as vast as the distance between Heaven and Hell. There is a chasm between the two, and the bosom of Abraham on only one side of it." - Wilson, AC, p40.