When was Saul of Tarsus already on the mind of God?
Saul of Tarsus was already on God's mind in eternity past. Scripture indicates God separated him from his mother's womb and preordained the timing of his conception, formation, birth, and calling by grace. His salvation was not earned but according to God's purpose and grace.
Les explains that Paul, formerly Saul of Tarsus, was steeped in the tradition of the fathers, but as he comes out of those traditions he points to God, who separated him from his mother's womb. Les asks when Saul was already on God's mind and answers, "In eternity past." At the appropriate time, Saul's mother conceived, and the baby in her womb was all part of God's preordained plan. God formed him in the womb, brought him to birth, and called him by His grace. Though Paul had been a persecutor who hated Jesus of Nazareth, God saved him not because he deserved it or earned it, but by grace. God's purpose was to reveal His Son in him—the resurrected, crucified, and risen Christ.
But when it pleased God, who separated me from my mother’s womb, and called me by his grace,