In Isa 46:10 we read (NASB) -
Declaring the end from the beginning, And from ancient times things
which have not been done, Saying, 'My purpose will be established, And
I will accomplish all My good pleasure'
The fact that God is omniscient (= knows all things, Job 37:16, Ps 139:1-18, 147:5, 1 John 3:20, Isa 46:9-11) means that he also knows all things in advance. This omniscince and foreknowlege allow God to select/choose people in advance for special work and ministry.
David expressed a similar idea in Ps 139:4 -
Even before a word is on my tongue, You know all about it, O LORD.
See also V16. The Cambridge commentary also suggests an element of choice about God's omniscience -
- I knew thee] meaning not mere acquaintance, but choice as a consequence of knowledge. The parallelism of contrast, frequent in the
poetical books of the Bible, shews this to be the sense of the word in
Psalm 1:6, “The Lord knoweth the way of the righteous, but the way of
the wicked shall perish”; cp. Genesis 18:19, “For I have known him, to
the end that he may command his children and his household after him,
that they may keep the way of the Lord”; Amos 3:2, “You only have I
known of all the families of the earth: therefore I will visit upon
you all your iniquities.”
Barnes has something similar:
Rather, "Before I formed thee in the belly." I approved of thee (as
one fit for the prophetic office)," and before thou camest forth from
the womb" I made thee holy (dedicated thee to holy uses); I have
appointed thee (now by this public call to be) "a prophet unto the