Saturdays with Calvin #41

Here it will be proper to point out the titles which the Scripture bestows on the Spirit, when it treats of the commencement and entire renewal of our salvation. First, he is called the “Spirit of adoption,” because he is witness to us of the free favor with which God the Father embraced us in his well-beloved and only begotten Son, so as to become our Father and give us boldness of access to him; no, he dictates the very words, so that we can boldly cry, “Abba, Father.” For the same reason, he is said to have “sealed us, and given the earnest of the Spirit in our hearts,” because, as pilgrims in the world, and persons in a manner dead, he so quickens us from above as to assure us that our salvation is safe in the keeping of a faithful God. 

Institutes of the Christian Religion 3.1.3 John Calvin, translated by Henry Beveridge, Hendrickson, pp. 350.