How did Jesus emphasize the necessity of conversion?

Answer

"Verily I say unto you, Except you be converted, and become as little children, you shall not enter into the
kingdom of heaven!' Matt. 18: 3.

By what is this cleansing from sin and fitting for God's service accomplished?
How is this expressed by Mark?
What name is given to the third state of the church?
What will be the third plague?
What must take place before the dead can praise God?
What is the last enemy to be destroyed?
Before he was afflicted, what did he do?

Questions & Answers are from the book Bible Readings for the Home Circle