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.

Upon what basis is justification granted?
Why did the apostle say this duty was so imperative?
How extensively is this message to he proclaimed?
What did Constantine's law require?
What day does the commandment say is the Lord's?
How is the church at the first advent described?
How was the faithfulness of this church commended?

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