After a violent storm one night, a large tree, which over the years had become a stately giant, was found lying across the pathway in a park. Nothing but a splintered stump was left. Closer examination showed that is was rotten at the core because thousands of tiny insects had eaten away at its heart. The weakness of that tree was not brought on by the sudden storm; it began the very moment the first insect nested within its bark.
Jesus said "Blessed are the pure in heart; for they shall see God". Matthew 5:8
That is one of the greate utterances in the Bible - only those with purified hearts will see God.