The word “apostle” means “one who is sent.” So the word can have a very general meaning of some persons sent by others on a special mission (e.g. 2 Corinthians 8:23; Philippians 2:25). In that case no special religious authority is implied because the sender is not an authority and does not intend to invest the “apostles” with authority they don’t possess.
In determining what authority an “apostle” has, we should ask: What authority does the sender have who sent the apostle as his authorized spokesman? And: How much of that authority did the sender give to his representative?
In a sense all missionaries, truly called by God, are sent by Christ as his representatives and should be able to say, “We are ambassadors for Christ, God making His appeal through us. We beseech you on behalf of Christ, be reconciled to God” (2 Corinthians 5:20). In order to be an authentic missionary one needs to be “sent.” “How shall they preach unless they be sent?” (Romans 10:15)
So these missionaries are authorized by the risen Christ, but we would not say that Jesus imparts to them the degree of authority that he gave to the original apostles whose teaching now stands in the New Testament. Their authority must constantly defer to the New Testament and prove itself by conformity to what the original spokesman of the Lord taught.
We would probably do well to avoid using the term today for missionaries and church planters, because using it may well create a confusion that could serve to lessen the unique authority of original apostolic teaching.
Less than apostolic,
Pastor John