Romans 8 16
The Spirit himself agrees with us that we're God's children.
Compare with other 3 random translations
AMP Romans 8:16The Spirit Himself testifies and confirms together with our spirit [assuring us] that we [believers] are children of God.
LSV Romans 8:16This One—the Spirit—testifies with our spirit, that we are children of God;
NCV Romans 8:16And the Spirit himself joins with our spirits to say we are God’s children.