Matthew Henry Commentary Mark 16:14-18

"And afterward he was manifested unto the eleven themselves as they sat at meat; and he upbraided them with their unbelief and hardness of heart, because they believed not them that had seen him after he was risen. And he said unto them, Go ye into all the world, and preach the gospel to the whole creation. He that believeth and is baptized shall be saved; but he that disbelieveth shall be condemned. And these signs shall accompany them that believe: in my name shall they cast out demons; they shall speak with new tongues; they shall take up serpents, and if they drink any deadly thing, it shall in no wise hurt them; they shall lay hands on the sick, and they shall recover." — Mark 16:14-18 (ASV)

The evidences of the truth of the gospel are so abundant that those who do not receive it may justly be reproached for their unbelief. Our blessed Lord renewed his choice of the eleven as his apostles, and commissioned them to go into all the world to preach his gospel to every creature. Only he who is a true Christian shall be saved through Christ. Simon Magus professed to believe and was baptized, yet he was declared to be in the bonds of iniquity (see his history in Acts 8:13–25). Doubtless, this is a solemn declaration of that true faith which receives Christ in all his characters and offices, and for all the purposes of salvation, and which produces its right effect on the heart and life; not a mere assent, which is a dead faith and cannot profit.

The commission of Christ's ministers extends to every creature throughout the world, and the declarations of the gospel contain not only truths, encouragements, and precepts, but also most solemn warnings. Observe what power the apostles were to be endowed with, for confirming the doctrine they were to preach. These were miracles to confirm the truth of the gospel and means of spreading the gospel among nations that had not heard it.