The Torah says: "Sanctify yourselves and be ye holy" (Leviticus 20:7).
This means that in those actions that are not specifically prescribed by the Halachah, there is great opportunity for sanctification.
Similarly, within the prescribed limits of Halachah, a person may be as unholy as the most wicked, and thus be separated from God.
Even the greatest of men are structured this way—those potentially capable of the highest sanctity are also more vulnerable to the force of the evil impulse.
That is, the one who instincts are stronger is just as capable of being a saint as a sinner.
The point is to utilize the opportunity presented by one's potential.
–Rabbi Adin Steinsaltz
From The Long Shorter Way, Ch. 27, by Rabbi Adin Steinsaltz