Jonah was in the fish’s belly for 3 days, just as Jesus was in the tomb. Jesus died and rose from the dead after 3 days.
Jesus said in Matthew 12:40, “For as Jonah was three days and three nights in the belly of a huge fish, so the Son of Man will be three days and three nights in the heart of the earth”.
When Jesus died on the cross and rose from the dead, he saved us from the death. Jesus said, “I am the resurrection and the life. He who believes in me will live, even though he dies and whoever who believes in me will never die”. (John 11:25-26)