1 John 2:5
But if anyone keeps His word, the love of God has been truly perfected in him. By this we know that we are in Him:
Berean Standard Bible
But whoso keepeth his word, in him verily is the love of God perfected: hereby know we that we are in him.
But God’s love has most certainly been perfected in whoever keeps his word. This is how we know that we are in him: