Luke 22:66-71 NIV
[66] At daybreak the council of the elders of the people, both the chief priests and the teachers of the law, met together, and Jesus was led before them. [67] “If you are the Messiah,” they said, “tell us.” Jesus answered, “If I tell you, you will not believe me, [68] and if I asked you, you would not answer. [69] But from now on, the Son of Man will be seated at the right hand of the mighty God.” [70] They all asked, “Are you then the Son of God?” He replied, “You say that I am.” [71] Then they said, “Why do we need any more testimony? We have heard it from his own lips.”

The Messiah/Christ (Hebrew/Greek) translates as the ‘anointed one’ and harks back to the very beginning of Israel’s identity as a nation. Their first high priest, Aaron (brother of Moses) was anointed by Moses, on God’s instructions, to act as a conduit to God.

Exodus 29:4,7 NIV
[4] Then bring Aaron and his sons to the entrance to the tent of meeting and wash them with water. [7] Take the anointing oil and anoint him by pouring it on his head.

So, the chief priests had a lot at stake if Jesus was to be known as the great High Priest, the anointed one. Jesus knew this, and knew they would try to trick him with their questions, as we’ve seen before. At no point in this conversation does he admit to being the messiah, or the Son of God but that didn’t matter to them - they still used their own questions as ‘evidence’ of his blasphemy to take to the Romans (the Jews were not authorised to give the death penalty)