Mark 16:17

And these signs shall follow them that believe
Not all of them, but some; and not always, only for a time; and which were necessary for the confirmation of the Gospel, and the establishment of Christianity in the world; and not only believing hearers, but believing ministers of the word, are chiefly designed; and this is said, for the encouragement both of those that preach the Gospel, and of them that hear, believe and obey. The Persic version, contrary to all others, reads, "ye shall show signs and wonders to them that believe not"; see ( 1 Corinthians 14:22 ) .

In my name shall they cast out devils;
so the Apostle Paul dispossessed the damsel, that had a spirit of divination; commanding the spirit, in the name of Jesus Christ, to come out of her, and it did; and evil spirits also went out of others, through his means, by the power of Christ, ( Acts 16:18 ) ( 19:12 ) ; and this power continued for a considerable time among the saints: the phrase "in my name", is in the Arabic version, joined to the word "believe", in the preceding clause; and is omitted in the Persic version, but is rightly retained by all others in this place; for by the power and authority of Christ, and not their own, and by calling upon, and making use of his name, such miraculous operations were wrought by the apostles:

they shall speak with new tongues:
or languages, not such as were new made, and had never been heard and known before; but foreign languages, such as they had never learned, or were able to speak, or understood before; and this not only did the apostles on the day of pentecost, but even common believers at other times, ( Acts 2:4 Acts 2:6 Acts 2:11 ) ( Acts 10:45 Acts 10:46 ) ( 1 Corinthians 12:10 1 Corinthians 12:28 1 Corinthians 12:30 ) ( 1 Corinthians 14:13 1 Corinthians 14:18 1 Corinthians 14:26 1 Corinthians 14:27 ) .