Galatians 5:7 Ye did run well; who did hinder you that ye should not obey the truth?
8 This persuasion cometh not of him that calleth you.
9 A little leaven leaveneth the whole lump.
Paul is telling them that they started out correctly. They were running the race of life well. Now they have listened to those who would come in and destroy. We must apply the blood of Jesus to our ear, so only things of God will be heard in our inner mind. We should not listen to others, and let them sway us. We should be thoroughly convinced, and never waver in our belief. They have listened to another doctrine other than what Paul had brought. The Lord God of heaven called you, stay with Him. God did not send the message to get back under the bondage of the law. This is the same thing as saying; one rotten apple will ruin the whole barrel, if it is not removed. Leaven is sin. It is a sin to doubt the message of grace. Anything that displeases God is sin. Faith is the only thing that pleases God. It seems that some of these people in the church were listening to those that still followed the law.