Allāh the Exalted removes the evil effects of sins in several ways. Some of the means come from the slave, while some come from other than him. Sins are expiated by the following means:
1️⃣st: Sins are expiated by sincere repentance. Surely, the one who repents from sin is like the one who has no sin.
2️⃣nd: Sins are expiated when the slave seeks Allāh’s forgiveness.
3️⃣rd: Sins are expiated by performing good deeds that wipe away evil deeds. ‘Verily, the good deeds remove the evil deeds.’ ²
4️⃣th: Sins are expiated when the person is afflicted with calamities, because calamities are expiation for sins.
5️⃣th: Sins are expiated when the angels seek forgiveness from Allāh on behalf of the person.
6️⃣th: Sins are expiated when the believers pray for the person.
These six matters occur during the person’s lifetime.
7️⃣th: Sins are expiated if the person suffers a difficult, agonizing death.
This occurs when the person departs this world.
8️⃣th: Sins are expiated when the person experiences the horror of seeing the two angels in the grave, the squeezing of the grave, and the difficulties therein.
9️⃣th: Sins are expiated when those whom Allāh gives permission to intercede, intercede on behalf of the sinners.
1️⃣0️⃣th: Sins are expiated when the Most Merciful of those who show mercy (Allāh) has mercy upon the sinners.
If the person is void of these means, it is inevitable that he will enter the Hellfire. His stay in the Hellfire will be proportionate to how long the filth remains in him, for surely, Allāh has prohibited Paradise for all who are not pure.
Thus, as long as filth remains in him, he will remain in the Hellfire to be cleansed.
Shaykh-ul-Islām Ibn Taymiyyah said in his book The Sickness of the Hearts and Its Cures: “Whoever misses these ten means, let him blame no one except himself. The Prophet ﷺ narrated that Allāh the Exalted said:
يَا عِبَادِي إِنَّمَا هِيَ أَعْمَالُكُمْ أُحْصِيهَا لَكُمْ ثُمَّ أُوَفِّيكُمْ إِيَّاهَا فَمَنْ وَجَدَ خَيْرًا فَلْيَحْمَدِ اللَّهَ وَمَنْ وَجَدَ غَيْرَ ذَلِكَ فَلاَ يَلُومَنَّ إِلاَّ نَفْسَهُ
“‘O My slaves, they are merely your actions which I am recording for you, then I will requite you for them. Whoever finds it to be good, let him praise Allāh, and whoever finds it to be otherwise, let him blame no one but himself.’ ” ³
¹ Taken from Preparations for the patient
² Surah Hūd 114
³ Sahih Muslim 2577
Book: One Hundred Pieces of Advice By Ibn Al Qayyim | Translated by Rasheed Barbee | Authentic Statements Publications | Page 32-33