Why do people need to be shaken up with biblical truths?
People need to be shaken up with biblical truths because many live under an illusion, hearing Scripture casually and dressing up religion on Sunday while hoping to spend eternity with their Creator. One day Jesus Christ will judge all men according to Paul's Gospel; everyone will stand lost or saved by what they do with Christ's death, burial, and resurrection.
Les teaches that this is scary, but sometimes people have to be scared a little bit and shaken up. They cannot just take these things in one ear and out the other, dress it up on Sunday morning for an hour, and then hope to spend eternity in the presence of their Creator; it is not going to happen. Paul makes several warnings that have scared him over the years, not for himself but for people living an illusion. He points to Galatians 5 and the coming day when Jesus Christ will judge all men according to his Gospel. Everybody will stand as lost or saved by what they have done with Paul's Gospel, which is that Christ died, was buried, and rose again. The purpose is to face people with biblical truths now, because one day they are going to be faced with them.