Signs follow those who believe.

"And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues;  They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover." (Mark 16:17-18)

"And these signs shall follow them that believe—in my name shall they cast out devils; they shall speak with new tongues; they shall take up serpents; and if they drink any deadly thing it shall not hurt them; they shall lay hands on the sick and they shall recover;" (Mormon 9:24)

"But, behold, faith cometh not by signs, but signs follow those that believe." (D&C 63:9)