Esau was the firstborn twin, Jacob being his younger brother. Their parents were told before their birth that the “older shall serve the younger” (Gen 25:23). Isaac, the heir of the blessing of Abraham (Gen 26:3–4), was therefore to pass this blessing on to Jacob, not Esau his firstborn.
However, because of his love of food, Isaac set out to bless Esau, once he brought him a delicious meal (Gen 27:2–4). Then, through deceit and the help of his mother, Jacob actually got the blessing for himself (Gen 27:27–29). And so, through much sinfulness, God upheld his plan of the older serving the younger.
Hebrews 12 refers to this incident briefly:
“…like Esau, who sold his birthright for a single meal. For you know that afterward, when he desired to inherit the blessing, he was rejected, for he found no chance to repent, though he sought it with tears.” Hebrews 12:16–17 ESV
There has been much discussion over what “it” refers to. There are three nouns which it could refer to:
“…to inherit the blessing, he was rejected, for he found no chance to repent, though he sought it with tears.”
Did he seek the blessing, a chance to repent, or repentance itself. In Greek, the gender of the pronoun “it” is feminine meaning that “it” can only refer to “blessing” or “repent” (though there does not seem to be much difference in meaning between seeking a chance to repent or seeking to repent). While there are proponents for both of these options, many have a theological problem with Esau not being able to find “repentance” which he sought it with tears, since repentance ought to be available to all.
It seems best that “it” refers to the blessing. Genesis 27:38 explicitly recounts Esau weeping and asking his father for blessing also. Thus, Esau was not trying to repent, with tears showing his genuineness, and God rejected him. He selfishly wanted the blessing.
However this “blessing” was available to him, just not on the terms Esau wanted it.
The Abrahamic blessing, which was passed onto Jacob, was a blessing with the purpose of seeing all the families of the earth blessed (Gen 12:3). This promise of blessing the world passed down through the “seed of Abraham.” All the families of the world would be blessed “in” this seed.
Esau was not the individual heir of this blessing, Jacob was. In other words, Esau was not the “seed” in whom all the earth would be blessed. Nonetheless, Esau could still be a recipient of this blessing transmitted by the seed of Abraham—namely Jacob in Esau’s day.
We later see that Christ is the “seed of Abraham” (Gal 3:16) and the blessing of Abraham is in fact the gospel message of justification by faith (Gal 3:7–9)! All those “in” Christ have been blessed, that is, they have been justified by faith.
Esau sought the blessing with tears, but did not find it because he sought it on his own terms. He wanted to be the “seed of Abraham.” Had he had faith in God promises looking to the “seed of Abraham” to receive his blessing, he would have in fact been blessed.
Repentance is available to all. All those who repent and believe will be justified (Mk 1:15, Rom 3:22–24), that is, will receive the blessing of Abraham. It was not that Esau sought repentance with tears, but he sought to be the “seed of Abraham” with tears. He did not find a chance to repent from this selfishness. Had he repented, he would in fact have received the blessing found “in” the seed of Abraham.