...To what shall I liken the kingdom of God? It is like leaven which a woman took and hid in three measures of wheat flour or meal until it was all leavened (fermented). Luke 13:20-21 [AMP]
I love to make bread and I know that only a small amount of yeast (leaven) is needed to make a large quantity of dough rise.
Yeast is often used in Scripture to denote a bad influence, but there seems no reason for taking that away from this example Jesus is using. The point is that a small quantity of yeast makes moves throughout a much larger mass. So, with the kingdom. yeast works quietly and unseen, and the kingdom works through Christ’s influence on people’s hearts, not in anything merely external and visible. It is worth noting that yeast works from inside: it cannot change the dough while it is outside. But it is also important that the power to change comes from outside: the dough does not change itself.
Everything we need from the Lord is deposited in us when we accept His Son as our personal ‘Sin Bearer”. We must allow ourselves to be changed from the inside out; that process, when we listen and apply what God is revealing to us, is one that results in nothing less than an outward demonstration of that work through fruit.