The biblical idea of ‘gospel’ has its roots in Isa 40-66, where in the Septuagint translation the Greek word euangelizomai (to bring good news) is used of the message of Jerusalem’s deliverance from bondage and the wider deliverance of the oppressed.

Isa 61:1-2 provided the text for Jesus’ first preaching at Nazareth (Lk 4:17-21), in which he declared the this Scripture had been fulfilled in him.  The ‘gospel of the kingdom’ is elaborated in the parables, which speak of God’s mercy towards the undeserving.

A new phase of the gospel begins with Jesus’ death and resurrection.  Jesus himself is the gospel: he is proclaimed as the one in whom God’s grace and mercy have drawn near, Rom 1:1-3.  In Christ, God has fulfilled his ancient promises to bless all nations.

F.F. Bruce (closely following C.H. Dodd) identifies the following elements in the message:-

• the prophecies have been fulfilled and the new age inaugurated by the coming of Christ;
• he was born into the family of David;
• he died according to the Scriptures, to deliver his people from this evil age;
• he was buried, and raised again the third day, according to the Scriptures;
• he is exalted at God’s right hand as Son of God, Lord of living and dead;
• he will come again to judge the world and consummate his saving work.

New Dictionary of Theology, art. ‘Gospel’