If they were inspired, then the four gospels must be true. If they are true, they must agree.
The four gospels do not agree.
Matthew, Mark and Luke knew nothing of the atonement, nothing of salvation by faith. They knew only the gospel of good deeds—of charity. They teach that if we forgive others God will forgive us.
With this the gospel of John does not agree.
In that gospel we are taught that we must believe on the Lord Jesus Christ; that we must be born again; that we must drink the blood and eat the flesh of Christ. In this gospel we find the doctrine of the atonement and that Christ died for us and suffered in our place.
This gospel is utterly at variance with, the other three. If the other three are true, the gospel of John is false. If the gospel of John was written by an inspired man, the writers of the other three were uninspired. From this there is no possible escape. The four cannot be true.
It is evident that there are many interpolations in the four gospels.
For instance, in the 28th chapter of Matthew is an account to the effect that the soldiers at the tomb of Christ were bribed to say that the disciples of Jesus stole away his body while they, the soldiers, slept.
This is clearly an interpolation. It is a break in the narrative.
The 10th verse should be followed by the 16th. The 10th verse is as follows: