There were religious leaders and teachers that were trying to convince the new converts that the Gospel was not true. They taught that you must still obey the law to please God. But the Good News is that we are now saved by grace through faith, not by works. Once we have accepted this truth, then the Holy Spirit comes to indwell us and lead us into all truth. The Holy Spirit could not be obtained by works or by obedience to the law. There is only one way to receive the Holy Spirit and that is by hearing the Word of grace and ,by faith, accepting Jesus as our Savior. Adding anything to God’s plan is nothing but vanity and man’s pride. We still have to answer the same question today. Are we saved by God who works miracles among us and provides us with His Holy Spirit? Yes, yes, we are! And once we accept Jesus, is there some great work we must do to be sure make it to heaven? The answer is no, works still cannot obtain our salvation. There are works that we should do, yes, but they do not add to our salvation. Our works are how we store up rewards in heaven.
26 For what profit is it to a man if he gains the whole world, and loses his own soul? Or what will a man give in exchange for his soul? 27 For the Son of Man will come in the glory of His Father with His angels, and then He will reward each according to his works.-Matt. 16:26,27(NKJV)