Have you heard of pilpul? This can be a constructive way for the truth to be revealed and for us to cast out doctrines that we have been holding on to that are false.
The best way to prove a point is quoting from reliable resources (especially the TaNaKh). Beyond that we use speculation, assumption, feelings, etc.
Case in point: I state that Yah'shua did not eat the Pesach meal and can back it up with multiple witnesses in the newer writings. The point is proven beyond a shadow of a doubt, yet many readers hold fast to their belief that he ate the Pesach meal. Why is this?
To use an analogy: "You spend two hours with someone proving that Yah'shua kept the Shabbat, you prove it using multiple witnesses in the newer writings and the person you have given the evidence to agrees that Yah'shua kept the Shabbat. Then when you ask what they are going to do about it, they tell you (you are right, but I need to pray about it).
Because the person let their feelings and desires, instead of their wisdom decide the matter, they are left to their own designs. But what if this person had a second witness that backed up the first. And this person turned from their selfishness and embraced the truth of the matter? What a joy this would be.
Yes the devil can be in the details but so is the truth.