Charles Ellicott Commentary 2 Kings 2:9

"And it came to pass, when they were gone over, that Elijah said unto Elisha, Ask what I shall do for thee, before I am taken from thee. And Elisha said, I pray thee, let a double portion of thy spirit be upon me." — 2 Kings 2:9 (ASV)

I pray you, let ... —Literally, And (i.e., well, then) let there fall, I pray you, a portion of two in your spirit, to me.

A double portion. —The expression used in Deuteronomy 21:7 of the share of the firstborn son, who by the Mosaic law inherited two parts of his father’s property.

Elisha asks to be treated as the firstborn among “the sons of the prophets,” and so to receive twice as great a share of “the spirit and power” of his master as any of the rest. “Let me be the firstborn among your spiritual sons;” “Make me your true spiritual heir;” not “Give me twice as great a share of the spirit of prophecy as you yourself possess,” as many have wrongly interpreted. The phrase, “a mouth of two,” seems to be a metaphor derived from the custom of serving honored guests with double, and even greater, messes (Genesis 43:34).

Ask what I shall do for you ... from you. —As a dying father, Elijah might wish to bless his spiritual son before his departure (Genesis 27:4). (Compare to 2 Kings 2:12 infra, My father, my father.)