Those who opposed Paul claimed that he made it too easy to follow God and be accepted by Him. The Jewish contingent had lived lives full of rules down to the very minutiae of existence, seeking for His approval, and now this so-called apostle was claiming that all you had to do was accept Jesus personally as your God and Saviour and you became a child of God! No need to get circumcised, no observance of the Sabbath necessary, not even keeping to the letter of the Jewish Law! It appears that these people could accept that you could become a believer even after you had committed some pretty bad sins, but your clean slate-cleaned by the death of Jesus Christ-then had to be kept completely clean in every way.
The Gospel of Jesus Christ is of free grace which remains there for us throughout our lives. How many of us have despaired at some chronic sin which threatens to destroy us, only for us to know again the merciful warmth of Christ's love embracing us once again as the Prodigal Son was embraced!
None of us are good enough, none of us will ever be good enough. It is time we stopped pretending that we have reached some standard of acceptance before God. It is not a system of credits and debits, which if the credits are greater than the debits we get to be accepted by God. We are all miserable failures, but by God's grace through Jesus Christ we can stand approved before Him. There is no other way, this is the only way.