Satan attacks from without to bring temptations within. The easiest thing in the world is to blame God for all of our troubles. If we don't blame God, often we blame others. Don't be deceived, my dear brothers. Every good and perfect gift is from above, coming down from the Father of the heavenly lights, who does not change like shifting shadows.
Temptations come from our own inward evil nature.
This evil nature gives birth to sin. Temptations come through failing to have a proper inward response to what Satan is doing to us. Temptations come from Satan and our own evil nature within. Sin results when we fail to respond correctly to God through obedience to his word. Sin results in heartache.