This is a crucial question for today and in many ways is answered in 1 Corinthians 15.1-4 as Paul writes about things of first importance.
The word 'evangelical' comes from the Greek word translated 'gospel' (verse 1), and is used to label a theological position, a body of truth which evangelicals believe is crucial and without which Christianity is not Christianity at all.
The term 'evangelical' emerged around the time of the Reformation when people like John Wycliffe in England and then Martin Luther in Germany, started to look at their Bibles and discovered how far the Church had drifted from the original teaching of Jesus and the apostles. The result was the divide with Roman Catholicism. Later the same term 'evangelical' was attached to the revival movements of the Holy Spirit in Britain and America in the 18th century as preachers like the Wesleys, Whitefield, Jonathan Edwards and others were powerfully used by God to sweep thousands of people into Christ's kingdom and change the whole moral and spiritual tone of these nations.
