not many are selected or achieve a certain accomplishment
—Only the top ten percent of applicants are admitted to the university, and only twenty percent of them will graduate. Many are called but few are chosen.

Jesus used the “Parable of the Wedding Banquet” to teach that while God calls all people into his kingdom, not everyone will accept the invitation or respond in the right way. In the story, a king sent out his servants to invite selected guests to a banquet for his son, but the people did not listen. Instead,

they were indifferent [made light of it] and went away, one to his farm, another to his business. (Matthew 22:5)

Some of the people even killed the servants. Of course, the king was angry, and he sent his army to kill the murderers and burn their city. The king then told his servants to go out and invite anyone they could find, both good and bad. Later, when the wedding hall was full, the king came to the guests and found one man who was not properly dressed.

And he said to him, “Friend, how did you get in here without wedding clothes?” But he had nothing to say. Then the king said to his attendants, “Tie him up hand and foot and throw him into the outer darkness, where there will be weeping and gnashing of teeth!” For many are called, but few are chosen.” (Matthew 22:12-14)

Make light of now means “to talk about something as if it’s unimportant or not serious.”