Jesus demonstrated awesome power when He cast demons out of people, but when He did so the demons confessed something, and Jesus wanted them to be quiet,

And demons also came out of many, crying out and saying,

“You are the Christ, the Son of God!” And He, rebuking them, did not allow them to speak, for they knew that He was the Christ (Luke 4:41).

If anyone knew the true identity of Jesus of Nazareth, it would be the demons, yet, they do not have the best credibility, and for that reason, Jesus silenced them.

The Bible records their confession, because they spoke the truth, but Jesus did not go looking for their endorsement, since they are the epitome of evil.