Genesis 37:3
1 But Jacob lived in the land where his father had stayed, in the land of Canaan. 2 This is the account of Jacob. Joseph, his seventeen-year-old son, was taking care of the flocks with his brothers. Now he was a youngster working with the sons of Bilhah and Zilpah, his father’s wives. Joseph brought back a bad report about them to their father. 3 Now Israel loved Joseph more than all his sons because he was a son born to him late in life, and he made a special tunic for him. 4 When Joseph’s brothers saw that their father loved him more than any of them, they hated Joseph and were not able to speak to him kindly.
Onkelos Genesis 37:3
1 And Jakob dwelt in the land of the habitation of his father, in the land of Kenaan. 2 These are the generations of Jakob. Joseph was a son of seventeen years; he kept the flock with his brothers; and he had been brought up with the sons of Bilhah, and with the sons of Zilpha, the wives of his father; and Joseph brought their evil report to his father. 3 But Israel loved Joseph more than all his sons, because he had in him a wise son, and he made him a variegated robe. 4 And his brothers saw that their father loved him better than all his brethren, and they hated him, and were not willing to speak with him peaceably.
Notes and References
"... Why should Jacob have favored Joseph over all his other sons? The Bible explains that Joseph was the 'son of his [Jacob's] old age' (Genesis 37:3), but this hardly seemed like an adequate reason to ancient interpreters. After all, Benjamin, Joseph's younger brother, was even more of a 'son of old age' to Jacob. Since he, no less than Joseph, was a son of Jacob's beloved wife Rachel, there really was no reason for Jacob to favor Joseph over Benjamin. If anything, Benjamin should have been loved more than any of the other brothers. Considering the situation, interpreters concluded that the Bible must have meant something else by the phrase 'son of his old age.' If Joseph was not younger than all the brothers, perhaps he surpassed them in some other way. Now, in the Bible 'old age' is frequently associated with wisdom: 'old man' is practically a synonym in biblical Hebrew for 'sage' or 'wise man' (see, for example, Ezekiel 7:26, 26:9, Psalm 105:22, Lamentations 5:14, Job 32:9, Ruth 4:9). Perhaps, then, in saying that Joseph was a "son of his old age," the Bible really meant he was a "son of his wisdom" - that is, Joseph was an exceptionally intelligent child ..."
Kugel, James L. The Bible as it Was (p. 248) Harvard University Press, 1998