Why does a loving God allow sin?

Many question the love of God in allowing so much sin, death, pain and degradation to run rampant and affect the entire world.
Here is a simple explanation of why God allows it to continue.

Of course, we do know that this will not go on forever and we look forward to the day when it is brought to an end and Earth is restored to a paradise for humanity to dwell in.

What are your thoughts about this? Feel free to leave your comments below.