Christ sent forth the apostles he had chosen, commissioning them to proclaim the gospel: “Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you; and lo, I am with you always, to the close of the age.” Strengthened by this mission, the apostles “went forth and preached everywhere, while the Lord worked with them and confirmed the message by the signs that attended it.”
The apostles were authorized by Christ to proclaim the gospel in His Name, and He “confirmed the message by the signs that attended it.” Now we must be forthright and concede that miracles do not universally attend the proclamation of the gospel (see for example Mt. 13:58, in addition to the experience of history). Furthermore, we likewise know that sometimes the powers of darkness are able to work marvels for the sake of deceiving men (e.g. Ex. 7 & 8; Dt. 13:1–3). If the message cannot be verified solely by signs and wonders, how shall we know the man whom God has sent?
The answer is by means of apostolic succession. This is another reason why apostolic succession is an essential doctrine of the Faith. Apart from it we have no reason to accept one party’s claims over another’s. It is an objective means by which we may identify Christ’s Church.