Genesis 37:29 When Reuben returned to the pit and saw that Joseph was not in the pit, he tore his clothes and returned to his brothers and said, “The boy is gone, and I, where shall I go?” Then they took Joseph’s robe and slaughtered a goat and dipped the robe in the blood. And they sent the robe of many colors and brought it to their father and said, “This we have found; please identify whether it is your son’s robe or not.” And he identified it and said, “It is my son’s robe. A fierce animal has devoured him. Joseph is without doubt torn to pieces.” Then Jacob tore his garments and put sackcloth on his loins and mourned for his son many days. All his sons and all his daughters rose up to comfort him, but he refused to be comforted and said, “No, I shall go down to Sheol to my son, mourning.” Thus his father wept for him. Meanwhile the Midianites had sold him in Egypt to Potiphar, an officer of Pharaoh, the captain of the guard.
Reuben tore his clothes as an expression of utter horror and mourning, because his weak stand for righteousness accomplished nothing. Joseph might as well be dead, because his father who loved him so would never see him again. This showed the cruelty of the sons of Israel was not directed only towards the favored son, but also towards the father who favored him. This was both a heartless way to bring the news and an evil lie. (Guzik)
How should his sons comfort him, when they were obliged to cover their wickedness with the sin of lying and hypocrisy, and when even Reuben, although at first beside himself at the failure of his plan, had not courage enough to disclose his brothers’ crime? (Keil and Delitzsch)
When Satan has taught men to commit one sin, he teaches them to try to conceal it with another; to hide theft and murder, with lying and false oaths: but he that covers his sin shall not prosper long. Joseph’s brethren kept their own and one another’s counsel for some time; but their villany came to light at last, and it is here published to the world. To grieve their father, they sent him Joseph’s coat of colours; and he hastily thought, on seeing the bloody coat, that Joseph was rent in pieces. Let those that know the heart of a parent, suppose the agony of poor Jacob. His sons basely pretended to comfort him, but miserable, hypocritical comforters were they all. Had they really desired to comfort him, they might at once have done it, by telling the truth. The heart is strangely hardened by the deceitfulness of sin. Jacob refused to be comforted. Great affection to any creature prepares for so much the greater affliction, when it is taken from us, or made bitter to us: undue love commonly ends in undue grief. It is the wisdom of parents not to bring up children delicately, they know not to what hardships they may be brought before they die. From the whole of this chapter we see with wonder the ways of Providence. The malignant brothers seem to have gotten their ends; the merchants, who care not what they deal in so that they gain, have also obtained theirs; and Potiphar, having got a fine young slave, has obtained his! But God’s designs are, by these means, in train for execution. This event shall end in Israel’s going down to Egypt; that ends in their deliverance by Moses; that in setting up the true religion in the world; and that in the spread of it among all nations by the gospel. Thus the wrath of man shall praise the Lord, and the remainder thereof will he restrain. (Henry)