1 John 4:13

13 This is how we know that we live in him and he in us: He has given us of his Spirit.

Read 1 John 4:13 Using Other Translations

Hereby know we that we dwell in him, and he in us, because he hath given us of his Spirit.
By this we know that we abide in him and he in us, because he has given us of his Spirit.
And God has given us his Spirit as proof that we live in him and he in us.