What I like about this study is this verse can be pertained to our(the elect's) salvation. In God's mind were were chosen to salvation in eternity past. God said it.
Before I formed thee in the belly I knew thee; and before thou camest forth out of the womb I sanctified thee, and I ordained thee a prophet unto the nations.
For further study - Jeremiah 1:1-21
God set Jeremiah as a prophet among the nations, and a prophet to the nations. The truth is that God did this for Jeremiah before he was born. But wait, verse 5 says God set Jeremiah aside, not only before he was born but, before he was even formed in his mother's womb. In fact, Jeremiah was "chosen" in the mind of God in "eternity past," verse 5.
Jeremiah 1:5 not only gives us background in the forming of the prophet but also is the evidence of when "life" begins, the big question today as it relates to abortion. Life does not begin at birth or even at conception. Life begins in the "mind of God" in eternity past. Now that settles the question.