Why could not Esau find forgiveness,after all "he sought it carefully with tears" ?

"Esau is the outstanding example of one who had full knowledge of the covenant of grace, but who in the hour of stress put a higher value upon personal comfort than upon the blessing of the Lord. When awakened at last to see his folly in some measure, he wept and pleaded for the blessing he had once bargained away; but it was too late. His father had given the blessing to Jacob, and could not repent. This, as I understand it, is what is meant by the solemn words, "he found no place of repentance, though he sought it carefully with tears." It is not that he himself could not repent of his former levity and profaneness; but he could not find a place of repentance in the mind of his father. However badly Jacob had acted, Isaac now knew it was the will of God that the blessing of Abraham should be given to the younger son. The lesson is a serious one. Divine things are not to be trifled with. Mercies despised at one time may be sought in vain later on. It behooves us all to be real, to be in earnest while it is called today."