When the evil inclination comes to connect to a person he is like iron before putting it into the fire. After it gets heated it turns back like fire.
Rabbi Chiya says that when the evil inclination comes to connect to a person, he is like another person that comes into the home as a guest because no one stopped him. Without objection from the homeowner, he gradually takes over the home until he has full control.
Rabbi Chiya says that he learned that from the story about King David.
2 Samuel 12:4
“וַיָּבֹא הֵלֶךְ לְאִישׁ הֶעָשִׁיר וַיַּחְמֹל לָקַחַת מִצֹּאנוֹ וּמִבְּקָרוֹ לַעֲשׂוֹת לָאֹרֵחַ הַבָּא לוֹ וַיִּקַּח אֶת כִּבְשַׂת הָאִישׁ הָרָאשׁ וַיַּעֲשֶׂהָ לָאִישׁ הַבָּא אֵלָיו.”
“Now there came a traveller to the rich man, and he was unwilling to take one of his own flock or herd to prepare for the guest who had come to him, but he took the poor man’s lamb and prepared it for the man who had come to him.”
‘a traveller came to the rich man’ is the evil inclination that comes to the ‘rich man’ that is the aspect of a person with Light. He comes closer to the rich man and tempts him to make a casual small sin. After no resistance, he becomes like the owner. ‘The man that came to him’ the Evil Inclination is served with a ‘lamb’ that doesn’t even belong to the rich man. It was taken without permission from a poor man’s heard.
The Evil Inclination is cold at the beginning as a simple iron and we don’t afraid to touch it but after he gets energy from us he turns hot like fire and can burn us. He starts by making us do a simple wrong that is insignificant but gradually pull the person to do greater sins until he transforms the person from good to sinner and evil.
We learn to restrict negative actions but when we are weak for some reason, we let our ‘door’ for the evil inclination to come in. He just challenges us with something small that we would consider as insignificant but after we do that, it becomes easier to repeat the same and even go bigger.
The simple example is when one is on a diet. He is tempted to take just a small bite from the delicious cake just to compliment the chef but after the first bite, more follows because the door was open without resistance.
The best way is to stop the first thought and remove it from our minds before it grows and manifests itself.