As soon as a person becomes self-aware, he realizes that his own worst enemy is himself—his evil inclination (also known as the Bestial Soul).
Without working to refine himself, the person’s natural state is to be wild, ungoverned, and dangerous, driven by selfish and destructive urges, as it is written: “A man is born like a wild ass” (Iyov 11:12) and “The inclination of man is wicked from his youth” (Bereshis 8:21). In fact, our Sages explain (Talmud Yerushalmi, Berachos 3:5) that the word mine’urav, “from his youth,” can also be interpreted as mine’arav, “from the moment he stirs,” i.e., from the moment a fetus stirs to go out into the world, it is confronted by the evil inclination.
So we are starting life, which is given to us in order to serve G–d, with a handicap. Thus, when a Jew decides to devote himself to serving Hashem, he has to overcome the resistance of the evil inclination, who was in charge first, and has been in charge all along, until the Jew reached this decision. He must actively push and force himself to think words of Torah, concentrate on the words of prayer, and perform Mitzvos. At the same time he should distance himself from any behavior or environment that may lead to temptation. This is the notion of Iskafya—bending and forcing oneself to do what one would rather not do, or restraining oneself from a forbidden or inadvisable deed that one desires to commit.
This holds true for someone born into a Torah-observant, and even chassidishe family who for whatever reason never took his heritage seriously, and reached a point of maturity in which he decided to do so.
In a different way, it is also applicable to a newcomer who was introduced to these teachings later in life and desires to embrace them. For although he has become excited about Torah and Mitzvos, since these teachings and practices are yet to permeate his inner self, part of him still desires to sin.
Regardless of the person’s background, the first step of the one who seeks to serve Hashem is Iskafya. However, this is only the beginning. The goal of divine service is that with time, not only will one’s external behavior in thought, speech, and action conform with Hashem’s will, but he will even change his inner self, and change his middos, his character traits. This is known as Is’hapcha, inner transformation.