My concern was because of the false brothers [those people masquerading as Christians] who had been secretly smuggled in [to the community of believers]. They had slipped in to spy on the freedom which we have in Christ Jesus, in order to bring us back into bondage [under the Law of Moses].

For if the inheritance [of what was promised] is based on [observing] the Law [as these false teachers claim], it is no longer based on a promise; however, God granted it to Abraham [as a gift] by virtue of His promise.

A little leaven [a slight inclination to error, or a few false teachers] leavens the whole batch [it perverts the concept of faith and misleads the church].