Gulielmus Bucanus (d. 1603) was a Swiss-French Reformed theologian. His Institutiones theologicae (Geneva, 1602) was one of the first systematic works of theology of the Reformed Church. In the excerpt below he discusses the gospel:
“It [the gospel] is a heavenly doctrine brought out of the secret bosom of God the Father by the Son, preached by the Apostles, and comprehended in the books of the New Testament, bringing a good and joyful message to all the world, namely, that mankind is redeemed by the death of Christ, the only begotten Son of God: for this remission of sins, salvation, and eternal life is prepared for all men, if so be they repent and believe in Jesus Christ.”
– Gulielmus Bucanus (d. 1603), Institutions of Christian Religion (Institutiones theologicae), p. 203
Theologia est doctrina Deo vivendi per Christum - Theology is the doctrine of living unto God through Christ 