In Matthew 12:38,39 the Pharisees and the Teachers of the law want to see a miraculous sign from the Lord. But read the answer of the Lord.

In Matthew 16:1,4 the Pharisees and Sadducees come to the Lord to test him. They want to see a sign from heaven. But read the answer of the Lord.

In Matthew 24:3 (Matthew 24:30) the disciples asking the Lord, “when will this happen, and what will be the sign of your coming and of the end of the age?” Read what the Lord as answering!