credentials

That which gives credit; that which gives a title or claim to confidence; the warrant on which belief, credit or authority is claimed, among strangers; as the letters of commendation and power given by a government to an embassador or envoy, which give him credit at a foreign court. So the power of working miracles given to the apostles may be considered as their credentials, authorizing them to propagate the gospel, and entitling them to credit.