“…nor did I go up to Jerusalem to those who were apostles before me; but I went to Arabia, and returned again to Damascus”
nor did I go up to Jerusalem
Paul did not need the approval of the apostles in Jerusalem for his gospel of grace. He did not check with Peter before he went out to preach.
to those who were apostles before me;
The apostles mentioned here were those apostles appointed earlier than Paul. They took up residence in Jerusalem. It would have been natural for them to teach him about the fundamentals of the faith. As Paul did not receive the gospel from human beings at his salvation, neither did he receive it from the apostles after his salvation. This shows his independence from the twelve apostles. But, by acknowledging them as apostles who came before him, he also gives them full recognition.
but I went to Arabia,
Instead of going to Jerusalem immediately after his salvation, he went to an area of Arabia known as Nabatea (in Transjordan to the south and east of Damascus of Syria). Arabia was a barren and thinly populated place. Paul needed to clarify the distinctions between law and grace. He spent decades steeped in legalism, so he needed time to orient himself to grace and think through the issues.
He went to Arabia to spend time with God in solitude. During this stay, God clarified the doctrine of grace to him. He did not get his message from human beings but from God. He wanted to get his message as clear as he could before he started preaching.
and returned again to Damascus
After the Lord clarified his message in Arabia, Paul returned to Damascus. He stayed there for a stretch of time and encountered persecution from the Jews.
“But Saul increased all the more in strength, and confounded the Jews who dwelt in Damascus, proving that this Jesus is the Christ. Now after many days were past, the Jews plotted to kill him. But their plot became known to Saul. And they watched the gates day and night, to kill him. Then the disciples took him by night and let him down through the wall in a large basket” (Acts 9:22-25).
God schools his saints in solitude.
God uses isolation and solitude to separate our souls from restless and busy lives. The Psalmists says, “Be still and know that I am God.” We need time to think about God. Solitude is God’s Wilderness Graduate School. It”s the place where we develop deep convictions about our relationship with the Lord and our service for Him.
God took many of his ministers to His Wilderness Graduate School. He took Moses there before He would use him. He also allowed Elijah to go through a wilderness experience. David spent some time there, while Saul hunted him like an animal. The Lord Himself spent forty days in the desert.