Some Scriptures Regarding the Gospel
1 Paul, a servant of Jesus Christ, called to be an apostle, set apart for the Good News of God, 2 which he promised before through his prophets in the holy Scriptures, 3 concerning his Son, who was born of the seed of David according to the flesh, 4 who was declared to be the Son of God with power, according to the Spirit of holiness, by the resurrection from the dead, Jesus Christ our Lord, 5 through whom we received grace and apostleship, for obedience of faith among all the nations, for his name's sake;
1 Corinthians 15:1-4
1 Now I declare to you, brothers, the Good News which I preached to you, which also you received, in which you also stand, 2 by which also you are saved, if you hold firmly the word which I preached to you - unless you believed in vain. 3 For I delivered to you first of all that which I also received: that Christ died for our sins according to the Scriptures, 4 that he was buried, that he was raised on the third day according to the Scriptures,
14 As Moses lifted up the serpent in the wilderness, even so must the Son of Man be lifted up, 15 that whoever believes in him should not perish, but have eternal life. 16 For God so loved the world, that he gave his one and only Son, that whoever believes in him should not perish, but have eternal life.
Regarding forgiveness during the Old Testament times:
23 for all have sinned, and fall short of the glory of God; 24 being justified freely by his grace through the redemption that is in Christ Jesus; 25 whom God sent to be an atoning sacrifice, through faith in his blood, for a demonstration of his righteousness through the passing over of prior sins, in God's forbearance; 26 to demonstrate his righteousness at this present time; that he might himself be just, and the justifier of him who has faith in Jesus.
15 For this reason he is the mediator of a new covenant, since a death has occurred for the redemption of the transgressions that were under the first covenant, that those who have been called may receive the promise of the eternal inheritance.