Upvote:2
In addition to Jeremiah 1:5, already quoted by Jonathon, we have the case of the man blind from birth:
1 And as Jesus passed by, he saw a man which was blind from his birth.
2 And his disciples asked him, saying, Master, who did sin, this man, or his parents, that he was born blind?
3 Jesus answered, Neither hath this man sinned, nor his parents: but that the works of God should be made manifest in him.
Since the man was born blind, and did not become blind later on, the implicit assumption here is that it's possible for a premortal sin to cause a congenital defect as punishment. Jesus didn't correct them by saying that there's no such thing as premortal existence, but instead said that the man's blindness wasn't punishment for any sin at all.
Taken together with Jeremiah 1: 5, we've got a fair amount of support for the spirit of man existing before mortality begins.
Upvote:4
It's clear that God formed our bodies in our mothers' wombs.
Job 31:15 NIV
Did not he who made me in the womb make them? Did not the same one form us both within our mothers?
Isaiah 44:24
“This is what the LORD says— your Redeemer, who formed you in the womb: I am the LORD, the Maker of all things, who stretches out the heavens, who spreads out the earth by myself,
Psalm 139:13
For you created my inmost being; you knit me together in my mother’s womb.
There really is no more scripture other then this one mention of God knowing us prior to our earthly state. Here is the one mention.
Jeremiah 1:5
“Before I formed you in the womb I knew you, before you were born I set you apart; I appointed you as a prophet to the nations.”
This mention could easily be interpreted that God is not limited by time, thus could very well have known exactly how He wanted to create you.
I would say that it boils down to this. God created mankind on earth, thus He created their souls at the same time.
Isaiah 45:12
It is I who made the earth and created mankind on it. My own hands stretched out the heavens; I marshaled their starry hosts.