Moses
Genesis 49:3BSB·traditional attribution

Reuben, you are my firstborn, my might, and the beginning of my strength, excelling in honor, excelling in power.

John Calvin Reformed

3. Reuben, thou art my first-born He begins with the first-born, not for the sake of honor, to confirm him in his rank; but that he may the more completely cover him with shame, and humble him by just reproaches. For Reuben is here cast down from his primogeniture; because he had polluted his father’s bed by incestuous intercourse with his mother-in-law.

Matthew Henry Presbyterian

Here is, I. The preface to the prophecy, in which, 1. The congregation is called together (Gen 49:2): Gather yourselves together; let them all be sent for from their several employments, to see their father die, and to hear his dying words. It was a comfort to Jacob, now that he was dying, to see all his children about him, and none missing, though he had sometimes thought himself bereaved.

Commenting on Genesis 49:1-4

John Gill Reformed Baptist

Reuben, thou art my firstborn,.... Jacob addressed himself to Reuben first, in the presence of his brethren, owned him as his firstborn, as he was, Gen 29:31 did not cashier him from his family, nor disinherit him, though he had greatly disobliged him, for which the birthright, and the privileges of it, were taken from him, Ch1 5:1.