One of the most beneficial of remedies is persisting in du’a.

Sins have many side-effects. One of them is that they steal knowledge from you.

From the perfection of Allah's ihsan is that He allows His slave to taste the bitterness of the break before the sweetness of the mend. So He does not break his believing slave, except to mend him. And He does not withhold from him, except to give him. And He does not test him (with hardship), except to cure him.

As you can taste a pot full of food with a spoon likewise someone's tounge can tell you about his heart.

Love of Allah is the power of the heart, the sustenance of the heart, the light of the heart.

The heart becomes sick, as the body becomes sick, and its remedy is al-Tawbah (repentance) and protection [from transgression]. It becomes rusty as a mirror becomes rusty, and its clarity is obtained by remembrance. It becomes naked as the body becomes naked, and its beautification is al-Taqwa. It becomes hungry and thirsty as the body becomes hungry, and its food and drink are knowledge, love, dependence, repentance and servitude.

The sinner does not feel any remorse over his sins, that is because his heart is already dead