But, [insert name of orthodox giant of the faith here] agrees with me!
This is a popular argument used on a regular basis by many different theologians, scholars, writers, bloggers, etc. The purpose of the argument is to declare that since such-and-such a person, whose orthodoxy can’t be challenged, held the same belief that is being argued for, then the belief must also be orthodox.
One common example goes something like this:
Many Reformed scholars and pastors, such as J.I. Packer, Francis Schaeffer, Charles Spurgeon, and J. Gresham Machen, hold/held to an old Earth. Since they are thoroughly orthodox in their beliefs, then it must be acceptable to hold to an old Earth.
Another example that is frequently used in the theistic evolution debate is say that since B. B. Warfield held to some version of theistic evolution and since he was a strong defender of the inerrancy of Scripture, then not only is theistic evolution compatible with Christianity, it poses no threat to the inerrancy of Scripture.
The problem with these type of arguments is that these appeals have their source in fallible men, instead of the only source of infallible truth, Scripture. Now, I realize that most people making an appeal to a giant of the faith would argue that these men used Scripture to form their beliefs. I’m sure that’s true. However, all men, aside from Christ, are subject to error. The Westminster Confession of Faith states it this way:
All synods or councils, since the apostles’ times, whether general or particular, may err; and many have erred. Therefore they are not to be made the rule of faith, or practice; but to be used as a help in both.
If we are not to use synods or councils as our “rule of faith” because of the potential for error, then it would be equally unwise to make any man, but Christ, our touchstone.
In Galatians, you see an example of how this should work. Peter, who was a well-known and well-respected leader within the community of believers, had bowed to the pressure of the circumcision party and stopped eating with the Gentiles. Paul did not say, “Oh well, Peter is one of the apostles. He knew Christ! His ministry has flourished and grown. He’s such a blessing to the community of faith. If he thinks it’s right to separate from the Gentiles, I’m sure he knows what he’s doing.” No, Paul “opposed him to his face, because he stood condemned.” (Gal. 2:11 ESV)
I’m not saying we shouldn’t listen to or learn from or consider what the giants of the faith have said on various topics. By all means, we should learn from those who have gone before us! But, we must always remember that they are men, just like us, just as capable of error as we are. Let us put our ultimate trust in the only infallible source of knowledge available to us. As the Reformers said, Sola Scriptura!