The Gemara teaches, “Rabbi Shimon ben Lakish said: A person’s evil inclination rises up against him every day and seeks to kill him. As the verse states, ‘The wicked one looks at the righteous person and seeks to kill him’ (Psalm 37:32). And if were not for the fact that the Holy One, blessed be He, helps him, he could not overcome it. As the verse states, ‘Hashem will not abandon him into its hand and will not condemn him to His judgment’ (ibid. 33)” (Succah 52b).

The Gemara here shows that Hashem created an evil inclination in man and gave it the power to overcome him. What's more, a person cannot overcome the evil inclination by himself, without the Hashem's help! The essence of the evil inclination is the desire for engaging in debauchery. As the holy Zohar teaches, “The essence of the evil inclination is the desire for forbidden relations.” Rebbe Nachman says that rectifying this area is a person's main rectification and the prime reason that he was sent into the world (Sichot Haran 115).

The holy Ohr Hachaim says that personal holiness is man’s most difficult challenge:

"It is known that all of the mitzvot that Hashem commanded His holy nation are mitzvot that a person can successfully keep, bending his will to do them—except for the mitzvah of separating oneself from forbidden relations. That is something that a person’s spirit desires and impels him to engage in, unless he makes a great effort to distance himself from two things: he distances himself from the influence of his sense of sight and he distances himself from the influence of his thoughts. But if a person does not do these two things, he cannot control this evil spirit…"

In other words, the holy Ohr Hachaim is saying that a person does not have the power to avoid debauchery. The only factors that can prevent him from doing so are having eyes that are entirely guarded and thoughts that are entirely clean. That is to say, in order to be protected from engaging in forbidden relations, a person must be a Holy of Holies. And what will all other people do, who are as far from this as the East is from the West? They need Hashem's help; if Hashem does not help them, they cannot succeed, because this challenge is beyond their power!

This means that our sages have explicitly stated that overcoming the evil inclination is beyond a person’s abilities. To overcome the evil inclination, we require assistance.

In our generation, in which we see the upsurge of the evil inclination and its cravings to such an alarming degree that they appear to have gone out of control, so that almost all people either surrender to their cravings and enter with them into dark and murky places, or else they try to overcome them with their own strength and fail each time, again and again, until they despair. Each time they are tested, they fail. That is because they are attempting to proceed on the basis of their own ability. Afterwards, they grow depressed, blame themselves and torment themselves. This is caused by their belief that they have the power to overcome their evil inclination, which leads them to think that they are terribly guilty. These two errors originate from the same source: they do not understand that overcoming the evil inclination is not within their power.

The central test of every individual is to overcome the powers of evil within himself—i.e., his evil inclination. The central powers of evil are the cravings and evil traits that rule over a person and dictate how to act. In most cases, the person knows that this behavior is very wrong, that it harms and damages him and his family, and that it is forbidden by the Torah. But at the moment that the craving overcomes him, that doesn’t interest him at all. And so against his will and against his better judgment, he is dragged after his evil cravings as though he is their captive. The Gemara here testifies that this is a spiritual law of nature. Understand this: alone, you cannot succeed. You need help. And, the only one that can help you is Hashem. Therefore, start praying to Him and asking for His help. This is something we can do right now.

So now we have the answer to our question. Hashem commands us to do something that we can't - alone. We must get close to Him and ask for His help to fulfill His commandment. That is exactly what Hashem wants.