Charles Spurgeon Commentary 1 John 4:13

"hereby we know that we abide in him and he in us, because he hath given us of his Spirit." — 1 John 4:13 (ASV)

By this we know that we dwell in Him, and He in us, because He has given us of His Spirit.

And His Spirit is the spirit of love. Wherever it comes, it makes a person love others and seek their good; and if you have that love in your heart, it came from God, and you dwell in God.