But he shall acknowledge the firstborn, the son of the hated, by giving him a double portion of all that is found with him; for he is the first of his strength, the right of the firstborn is his.
English: “Of all that is found with him” — of all that is found, and not of that which is only due to be found.
On the daf / in context: The firstborn’s double portion is limited to assets already in the father’s possession at death (muchzak). Assets that were only owed to the father (ra’uy) are divided equally among all the sons.
Type of Learning
Mi’ut from “yimatze lo” excluding ra’uy assets.
What Is Learned
The firstborn receives a double portion only in property already held by the father at the time of death, not in property that was merely due.