Religion, wherever it is found, has a common thread: ‘Do better and God will be more pleased with you; do well enough and God will accept you’.  It is not true but it appeals to human nature that believes it can achieve God’s approval by following the rules and doing good.  But the gospel is radically different.  It was a difference which Paul could not understand until he encountered the Living Jesus (Acts 26:12-20).  

These verses are part of a longer passage (Galatians 2:11-21) which started by Paul explaining why he had challenged Peter to stay true to the gospel and stop pulling others back to religious legalism (Galatians 2:11-13).  The Law of Moses could never save anybody; it could only define sin and accuse people who broke the law.  But when Jesus died, He was punished for all sins and so the law has no more power to accuse those who are safe in Christ.  

Where does the power of God come from?  Obviously, only from God.  Yet some false teachers were saying that God gives His Spirit to those who are good and deserve His presence.  But that cannot be true, Paul argued.  The biggest miracle is that a sinful person can be made a child of God.  That is God’s free gift and only happens when the Holy Spirit comes into a person who believes in Jesus (Ephesians 2:8-9).  After that He may enable all kinds of other miracles, not because the person does everything right, but because God chooses to give His grace to those who believe the gospel (Hebrews

Paul had been a devoutly religious Jewish theologian.  Before he met Jesus, he believed that his religious observance would make him right with God.  In other words, Paul relied on his own ability to keep the Jewish law to gain God’s approval.  His standing before God depended on what he could do (Philippians 3:4-6).