Qur'anic verses - Confirming the Law & the Gospel:

Guidance, with reference to conduct; light, with reference to insight into the higher realms of the spirit.

The religion is indeed one, and Jesus, peace be upon him, came to assert this fact. Similar meaning is explained in the Bible, Matthew 5:17, as such, Jesus' preaching was in fulfilment of the Law, as well as the Gospel.

The New Testament is a compilation of records written long after the life of Jesus on earth. These records should not be confused with the divine revelation as was sent down to Jesus, peace be upon him, in form of the Holy scripture. There is no evidence that the scripture had survived in its original form.