Galatians 5:9
“A little leaven leavens the whole lump of dough.”
I'm not sure how this works, but it appears that the leaven spreads like virus throughout the loaf which allows it to rise. One of God's endless miracles. Leaven throughout scripture refers to evil. It certainly is the case here. The false teachers came in and shared a contrary gospel which caused the entire Galatian church to go astray, just like leaven.
This principle of how evil spreads is constant throughout the spectrum of evil. Hebrews 12:15 speaks of having a bad attitude, "See to it that no one comes short of the grace of God; that no root of bitterness springing up causes trouble, and by it many become defiled". It takes work to have a good attitude. We have to go against the flow. Some take joy in tearing others down by gossip. Our interrupting them or telling them we don't want to hear it, upsets them.
To avoid evil, scripture gives this advice, "Keep your heart with all diligence, for out of it spring the issues of life" (Proverbs 4:23). Our consciences will let us know when we have a wrong attitude. This passage tells us not to let it slide, but to do the right thing. Like a gardener that won't permit a single weed, so we are to root out evil.
Titus 1:15 shares a blessing as we remain in His grace. It says says, "To the pure, all things are pure; but to the defiled and unbelieving, nothing is pure. Indeed, both their minds and their consciences are defiled". As we walk in obedience and avoid evil, the Lord blesses us with innocence. It's like we have a teflon exterior, evil doesn't stick.
This doesn't mean we can't be tempted, just that the Lord's joy and innocence has a protective disinfectant way. A part of the Lord's Prayer comes to mind, "and keep us from evil". As we seek to obey in avoiding evil, He blesses our obedience and keeps us from evil.
The believer understands the powerful spread of evil and avoids it. The Lord supercharges us and aides us in holiness. However, at times we will stumble. Jesus shares this truth in John 13:10, 'Jesus says to him, "The one having been bathed has no need to wash, except the feet, but is wholly clean. And you all are clean, but not all."' As we walk through this world our feet get dirty, we will stumble and sin. We come to the Lord to confess and He forgives us. After Jesus washes our feet we get back on the highway of holiness.
Lord, thank You for Your many blessings, keeping us from evil being one. Help us to avoid evil's power and to keep our hearts clean.