“And it came to pass, when Israel dwelt in that land, that Reuben went and lay with Bilhah his father's concubine: and Israel heard it. Now the sons of Jacob were twelve:”
King James Version (KJV)
Matthew Henry's Concise Commentary
35:21-29 What a sore affliction Reuben's sin was, is shown, and Israel heard it. No more is said, but that is enough. Reuben thought that his father would never hear of it; but those that promise themselves secrecy in sin, are generally disappointed. The age and death of Isaac are recorded, though he died not till after Joseph was sold into Egypt. Isaac lived about forty years after he had made his will, chap. 27:2. We shall not die an hour the sooner, but much the better, for timely setting our hearts and houses in order. Particular notice is taken of the agreement of Esau and Jacob at their father's funeral, to show how God had wonderfully changed Esau's mind. It is awful to behold relations, sometimes for a little of this world's goods, disputing over the graves of their friends, while they are near going to the grave themselves.
“These are the sons of Bilhah, which Laban gave unto Rachel his daughter, and she bare these unto Jacob: all the souls were seven.”