1 John 4:4

You, dear children, are from God and have overcome them, because the one who is in you is greater than the one who is in the world.

(v4, NIV)

John is reassuring his readers who he addresses as dear children. These people are from God and are not from the world. Those who are from the world are those who John spoke about previously as having a different spirit. The spirit in them is the spirit of the antichrist. In addition, these who are from God have overcome those who are from the world. How is it that they are overcome? It is because of the one who is in those who are from God. The one who is in them is greater than the one who is in the world.

This reminds me of back in chapter three when John was talking about our hearts. He was talking about our hearts condemning us. However, the comfort is that God is greater than our hearts. Similarly, he who is in us is greater than the one who is in the world. We take comfort in the superiority and power of God.