OK, I'll resist the temptation to start a new thread on this topic and will instead offer a shorter version of my response that will answer my question posed above about 3 biblical texts that imply the preexistence of the soul.
(1) Jesus's disciples apparently believe in the preexistence of the soul. This belief is implicit in the question they pose to Jesus about a man they encounter who has been born blind: "Rabbi, who sinned, this man or his parents, that he has been born blind (John 9:2)?"
Their question presupposes the concept of a premortal life during which good or evil choices can be made. Note that Jesus does not dispute their assumption, but rather insists that in this blind man's case he was born blind, so that God can be glorified through his healing. In
(2) The OT background of this belief is illustrated by Wisdom of Solomon 8:18-20: "As a child, I was by nature well endowed, and a good soul fell to my lot; or rather, being good, I entered an undefiled body." [This document is in the Catholic OT only.] In intertestamental Jewish thought, souls are created before the earth's creation: "All souls are prepared for eternity, before the composition of the earth (2 Enoch 23:5)." The Jewish Essenes of Jesus' day explain their preexistence this way: "The soul is immortal and imperishable. Emanating from the finest ether, these souls become entangled, as it were, in the prison house of the body. to which they are dragged down by a sort of natural spell (Josephus, Wars 2.9.11)."
(3) God's call to Jeremiah implies more than divine foreknowledge; it implies his soul's preexistence: "Before you were formed in the womb, I knew you, and before you were born, I consecrated you and appointed you a prophet to the nations (Jeremiah 1:5)." And Paul has Jeremiah's prophetic call in mind when he explains his own apostolic call: "He [God] who had set me apart before I was born (Galatians 1:15)."
None of these texts implies reincarnation. There is no evidence for Jewish belief in reincarnation in first century Palestine. The earliest evidence for a Jewish belief in reincarnation develops around the 7th century AD with the rise of Merkabah and Kabbala mysticism. The earliest evidence for Christian reincarnationism is the transjordanian Jewish sect called the Elchasaites which emerge in 102 AD. Some 2nd century Christian Gnostics also believe in reincarnation. It is often wrongly claimed that the church father Origen (c. 225 AD) embraces reincarnation. He does not believe that we repeatedly return to our earth for additional incarnations. But he comes close; he believes that our souls have continually migrated from other worlds to new worlds for new incarnations.