I agree with pinkdiamond so "yes".
If we're talking about the apostles of Christ, we're talking about those Christ sent to "go make disciples, *teaching* them all [Christ] taught [them]". If we're not following the doctrine of Christ's Apostles we're not following the doctrine Christ taught.
As a comparison, Christ said to beware of the leaven of the Pharisees, and scripture says by that he meant their doctrine/teachings. Christ also said "i am the way...Anyone who comes in another way is a thief." Then we have the Samaritan woman at the well who asked a question about doctrine ("should we worship on this mountain or not") where Christ replied "woman you don't know what you're actually worshipping for *salvation* is of the Jews". The Samaritans traditionally worshipped God using their own doctrine, altered from the original instructions, just like the Pharisees. So doctrine is important. As Christ said, those who worship God must do so in spirit AND in *truth*, and God said "do not add to or take away from".
We can have strong faith, but if we have false doctrine we can't be sure who we're actually worshipping.