In the Old Testament we find a situation in which Joshua asked the Lord a question and received a "No!" in answer. For it was the wrong question. He had asked whether God was on his side – but the actual question was whether Joshua was the one standing on God's side.

Are we standing on God's side? Are we living the way he wants us to live? Our behavior has consequences, in the natural realm just as in the spiritual. How we live, what we do or do not do, decides whether we are standing on the Lord's side or not.

"No!" is therefore a very important word. Some people think they cannot say "no". But it is absolutely necessary so that we do not get manipulated and do things we do not actually want to do at all. Saying "No!" helps us stay on the right side.

When Joshua was by Jericho, he lifted up his eyes and looked, and behold, a man was standing before him with his drawn sword in his hand. And Joshua went to him and said to him, "Are you for us, or for our adversaries?" And he said, No, but I am the commander of the army of the LORD. Now I have come.
Joshua 5:13-14

Let what you say be simply "Yes" or "No." Anything more than this comes from evil.
Matthew 5:37

But the wise answered, saying, No”, lest there not be enough for us and for you; go rather to the sellers and buy for yourselves.”
Matthew 25:9

Let your "yes" be yes and your No a No, so that you do not fall under judgment.
James 5:12