Hebrews 3:13 "but exhort one another daily, while it is still called "Today," lest any of you be hardened through the deceitfulness of sin."
My kids are constantly asking, "Why are they bad?" especially when referring to a movie or cartoon character. "What made them bad?" Interesting question. Besides just the simple and correct answer, "Sin."
In the past, I've talked of parenting, but I realize it's possible for godly parents to have ungodly children. Sin is the choice of the child. This verse in Hebrews is the verse I need to come back to.
We are hardened by the deceitfulness of sin. Period. Anyone is capable. O Lord, create in me a clean heart.