2 Corinthians 1:22
22 He who has also 1asealed us and given the Spirit in our 2hearts as a 3bpledge.
222 The Spirit, the earnest of God as our portion, is a foretaste to us; thus, here it says that He is in our hearts. Romans 5:5 and Gal. 4:6 refer to the matter of love and, hence, speak of the Spirit in our heart. But Rom. 8:16 refers to the work of the Spirit, since it says that the Spirit witnesses with our spirit. Our heart is a loving organ, but our spirit is a working one.