Genesis 27 lets us into the sight of circumstances which searched the heart of all concerned. We see the nature which left room for the mingled character which so evidently belonged to Jacob. He was a believer; but a believer in whom flesh was little judged, and not in him only, but in Rebecca also. Between them there is much to pain; and although Isaac might not be without feebleness and fault, there was deceit in both the mother and the son. As to Esau, there was nothing of God, and consequently no ground of complaint on that score. At the same time there was positive unrighteousness, of which God never makes light in any soul.
Hence we find that though the blessing was wrested fraudulently from Isaac, he is astonished to find where he had been drifting through yielding to nature; for indeed flesh wrought in Isaac, but for the time it ruled, I may say, in Rebecca and in Jacob. Shocked at himself, but restored in soul, he finds himself through his affections in danger of fighting against the purpose of God. Spite of all the faults of Rebecca and of Jacob, they at least did hold fast the word of God. On the whole it is a humiliating spectacle: God alone shines throughout it all as ever.
Isaac therefore, awakened to feel whence he was fallen, affirms the certainty of the purpose of God, and pronounces in the most emphatic terms that, spite of the manner in which Jacob had possessed himself of his blessing, he shall be blessed of God.