There are some questions we cannot answer now because God in His wisdom has simply not chosen to reveal this information in the Bible. In addition, our finite minds cannot fully comprehend the mind of God nor His ways, and we will have to wait until we meet Him face to face to understand completely.
In heaven we will have perfect understanding, as stated in 1 Corinthians 13:12: "Now we see but a poor reflection as in a mirror; then we shall see face to face. Now I know in part; then I shall know fully, even as I am fully known." Read also Isaiah 55:8-9. We must leave our questions with Him, resting in the assurance that He loves us perfectly and rules with perfect justice; read Romans 8:28.