The Torah tells us repeatedly to not take advantage of others – specifically the blind:
Thou shalt not curse the deaf, nor put a stumbling block before the blind, but shalt fear thy God: I am the Lord. (L. 19:14)
Cursed be he that makes the blind to wander out of the way. (D. 27:18)
It seems that we have an example of this happening in the Torah: Rivkah tells her son Jacob to confuse Isaac, in order to supplant the blessing Isaac planned to give to Esau. This happened “When Isaac was old and his eyes were too dim to see.” (G. 27:1)
It seems that the Torah teaches us a lesson here: taking advantage of the blind is not righteous behavior.
But this actually goes both ways! Because the Torah also seems to learn a lesson from Isaac’s behavior as well! After all, we are told:
And thou shalt take no bribe: for the bribe blinds the wise, and perverts the words of the righteous. (E. 23:8)
Thou shalt not wrest judgment; thou shalt not show partiality, neither take a bribe: for a bribe blinds the eyes of the wise, and perverts the words of the righteous. (D. 16:19)
What did Isaac do? He requested something special before giving the blessing:
“Take your gear, your quiver and bow, and go out into the open and hunt me some game. Then prepare a dish for me such as I love, and bring it to me to eat, so that I may give you my innermost blessing before I die.” (G. 27:3)
This request certainly might explain how Isaac was unable to see Esau’s failings clearly — these special meals obviously perverted the words of the righteous!
Note that the Torah’s injunctions are not against offering a bribe (even though we know that trying to bribe someone is wrong). Apparently, it was not wrong, per sé, for Esau to feed his father food that he loved – this might be the same thing as honoring one’s father after all. But the obligation to not take a bribe falls on the wise man!
Another example of how events in the first book of the Torah help us better understand the commandments that are found much later!