Who also declared unto us your love in the Spirit.
Your love (Colossians 1:4) - "to all the saints."
In the Spirit - the element IN which alone true love is found (Romans 14:17; Romans 15:30), as distinguished from that of those "in the flesh" (Romans 8:9). Even they needed to be stirred up to greater love (Colossians 3:12-14). Love is the first-fruit of the Spirit (Galatians 5:22).