“Hearken to me, you who pursue deliverance,
you who seek the Lord;
look to the rock from which you were hewn,
and to the quarry from which you were digged.
2 Look to Abraham your father
and to Sarah who bore you;
for when he was but one I called him,
and I blessed him and made him many.
"Look to the rock from which you were hewn . . look to Abraham your father."
The "look to" passages are put in parallel, showing they are speaking to the same thing, which is Abraham. The repetition is rhetorical.
"Abraham" is the "rock" from which the Jews were hewn and became many. His descendants are, so to speak, "chips off the ol' block."
This is really quite obviously unless one is diligently trying not to see it.
Nope; they come one after the other; meaning they speak to different things.
Isaiah 51:1 Look unto the Lord you that seek righteousness you that follow after unto me listen whence you are dug of the pit the hole and unto and unto whence you are cut the rock unto 2 alone for him that bore Sarah and unto your father Abraham unto look and increased and blessed him I called
Deuteronomy 32:18 Of the Rock that begat thee thou art unmindful, and hast forgotten God that formed thee.
Deuteronomy 32:15 But Jeshurun waxed fat, and kicked: thou art waxen fat, thou art grown thick, thou art covered with fatness; then he forsook God which made him, and lightly esteemed the Rock of his salvation.
God is the Rock, Abraham is not.