Institutes of the Christian Religion (1559) - John Calvin
Book 2 - God the Redeemer
Chapter 9 - Christ clearly revealed in the Gospel,
though known under the Law
Sections 1-2 - The Grace of Christ anticipated and manifested
Section 1 - The advantage of the community of the New Covenant
God showed He was our Father in the Old Testament.
The OT pointed Christ - Mal 4:2; 1 Pet 1:10, 12; Matt 13:16-17; Luke 10:23-24; John 5:46; 8:56; Heb 1:1-3; 1 Cor 10:4.
But the OT had value in itself for Israel.
Section 2 - The gospel preaches the revealed Christ
The Gospel, generally, includes God's promises of favor and mercy He made to OT saints.
"All those promises of free remission of sins... are counted as parts of [the Gospel]."
More fully, the Gospel is the revealing of Christ - Matt 4:17, 23; 9:35; Mark 1:1; 2 Tim 1:10; 2 Cor 1:20; John 1:51.
Section 3 - The [OT] promises are not abrogated for us
Servetus says they are, but that would mean we aren't waiting for the same salvation the OT saints were waiting for - Col 3:3; Rom 8:24; 1 John 3:2; 1 Tim 4:8.
The promises are the same - 2 Cor 6:16-7:1 - but are clearer in the NT.
Section 4 - The opposition between law and gospel ought not to be exaggerated
The contrast is legit - Rom 3:21-22; Gal 3:10-11.
"But the gospel did not so supplant the entire law as to bring forward a different way of salvation." Rom 3:21: "the Law and the Prophets bear witness to [the Gospel]."
"Where the whole law is concerned, the gospel differs from it only in clarity of manifestation."
Section 5 - John the Baptist
He held an "intermediate office" between law and gospel.
He prepares the way - Matt 11:11; John 1:23; Mal 4:5; John 5:35.
He preaches the Gospel, and baptizes with water as the apostles did - John 1:33.