Where Does Yetser Ha'ra Come From?

(7) Hashem formed (va'yitser, ​root word יצר) the human of the dust of the ground, and breathed into his nostrils the breath of life; and the human became a living soul.

(5) And Hashem saw that the evil of the human was great in the earth, and that every yetser of the thoughts of the human heart was only evil all day. (6) And Hashem regretted having created the human on the earth, and it grieved Him at His heart. (7) And Hashem said: ‘I will blot out the human that I have created from the face of the earth; from human to beast to creeping thing to fowl of the air; for I regret that I have made them.’

(21) And Hashem smelled the sweet smell; and Hashem said in His heart: ‘I will not again curse the ground for humanity’s sake; for the yetser of a person's heart is evil from his youth; I will not again smite every living thing, as I have done.

"From his youth" It says from his youth, (m'n'urayv, root word נער) from when he shook (n'na'er, root word נער) to come out of his mother's innards, the yetser ha'ra was given in him.

The yetser ha'ra is difficult, for even its Creator called it "bad", as it is written "for the yetser of a person's heart is evil from his youth"

Rabbi Yitzhak said a person's yetser renews upon him every day, as it is written "only evil all day."