Sin will crouch at your door

Siberia that experiences bitter cold always had unusual summer in 2016. That created wildfire. Permafrost soil loosened. There was sickness among children of herdsmen. It was fever, stomach pain and then children died. Emergency was declared in that area. Hundreds of sick people had to be airlifted. Scientists started their investigation and found they were exposed to toxins. Where did the toxin came from? “A heat wave has thawed the frozen soil there and with it, a reindeer carcass infected with anthrax decades ago.” In 1941 reindeers had died due to anthrax. The thawed animal carcass with anthrax that was buried under snow, got exposed due to the heat. That deadly toxins spread the disease. This anthrax lies in wait for favourable circumstances to emerge out as agents of disease and death. Like this deadly anthrax, sin that is presumed dead could come alive to destroy us.
God warned Cain that sin will crouch at his door and he has moral responsibility to overcome it. (Genesis 4:7) Instead of doing what was right and good, he was angry and envious of his brother who was doing right. Cain allowed sin to overcome him and he ended up as the first murderer. Even in the lives of believers, Paul warns that there is the principle of sin trying to raise its ugly head at any moment. (Romans 7)
James writes: “But each person is tempted when he is lured and enticed by his own desire. Then desire when it has conceived gives birth to sin, and sin when it is fully grown brings forth death.” (James 1:14,15) Desires of eyes, desires of flesh and pride of life are dangerous worldly principles that will destroy any human. (I John 2:16)
The Lord Jesus taught that what comes from inside is dangerous. (Matthew 15:11) Sinful habits could become active and alive when there is a favourable situation. Hence, being watchful is essential, not to allow Satan to use our desires and contexts to stumble and fall.
Am I watchful not to fall in sin?