The old Jewish law did not allow for freedom. Freedom implies you can make a choice. With Jewish law there is no choice. The laws were numerous, they burdened the people with trivial items, and created division between those who have and those who do not.
Jesus reminds his followers that the only sign they will know is the sign of Jonah. What is he referring to? Jesus has worked many cures, healed many people, and has performed many other signs. The leaders of the people continued to ask for more signs to prove to them who Jesus is. No matter what miracle Jesus would do it would not be enough to satisfy the religious leaders. They would ask for more.
It is not a sin to do research, ask questions, seek out more information. It becomes a sin when you choose not to make a decision but stay in a seek and search mode to avoid making a decision. Or choose an apathetic position to not choose. Neither option exercises freedom.
We were given a conscience to make decisions. God placed in our hearts the ability to understand what is right and wrong. He also gave us the freedom to choose. Exercise your freedom. Seek God through prayer.
May the Lord bless you in the name of the Father and of the Son and of the Holy Spirit. Amen