Isaiah 40:13

From the power of Jehovah, the writer passes to expatiate on His perfect and self-sufficing wisdom.

Who hath directed The verb is the same as "meted out" in the previous verse, and the transition from the literal to the metaphorical use is somewhat uncertain. From the idea of "weighing out" according to a fixed scale we get the notion of "regulating" or "determining"; cf. Ezekiel 18:25 (and pars.) "the way of Jehovah is not weighed out," regulated, i.e. is arbitrary. Or, on the other hand, the meaning might be "rightly estimated," "searched out" (as Proverbs 16:2; Proverbs 21:2). The first sense suits the context best; whether we render "direct" or "regulate" or "determine." LXX. probably read a different word; its τίς ἔγνω νοῦν Κυρίου is verbally cited in 1 Corinthians 2:16.

the spirit of the Lord denotes here the organ of the Divine intelligence (see 1 Corinthians 2:11). This is more likely than that the spirit is personified and then endowed with intelligence. The idea, however, does not appear to be found elsewhere in the O.T. The Spirit of God is ordinarily mentioned as the life-giving principle emanating from Jehovah, which pervades and sustains the world, and endows select men with extraordinary powers and virtues.

orbeing … him Better, perhaps: and was the man of His counsel who taught Him. "His" and "Him" refer of course to Jehovah, not the Spirit.