Yes / No
Why is it that some people cannot answer a simple yes or no to a fair question? Matthew 5:37 gives us the answer:
All you need to say is simply ‘Yes’ or ‘No’; anything beyond this comes from the evil one
One way we know that a person’s answer is from the evil one is when they cannot answer a simple and fair yes or no question. They do this because light has come into the world and they want to hide the true answer that they have in their heart because they know it is either condemning or they do not know the answer and cannot admit that. How do we know this? Because they would otherwise boldly state yes or no when defending their teaching. By the way. saying that you do not know is a good and acceptable answer because it takes humility and honesty to admit this and it means you are ready to learn.
Simply put, avoiding saying yes or no shows that a person has no faith in their own answer because they know they could get trapped by such simple but powerful questions. Here is the thing though. If they were honest they would welcome this, because the end result would be a win for the truth, and in turn people can change when they subject themselves to this kind of scrutiny. But they obviously do not want to change. So they try appear as righteous and knowledgeable by hiding the devil in the details with bloated answers because the truth matters less to them compared to their own reputation.
It a bit like a meal that tastes bad. To hide the taste you can use lots of sauce. It is sad but true that people engage in this practice. But at least we are aware of the reason this is done. As such, a person by default loses the debate when they cannot answer yes or not to a fair and simple yes or no question.