This is one of the eight verses which Abdullah Ibn Abbass mentioned (indicated before). The Prophet (saws) said:
“Whoever says “There is no God but Allah” will enter the Paradise”[1]
This is the greatness of this religion, no one can judge others and say this one is a believer and that one disbeliever, this one will enter the Paradise and that one will go to Hell.
(… إِنَّ اللَّهَ لَا يَغْفِرُ أَن يُشْرَكَ بِهِ ) (Indeed, Allah does not forgive association with Him,…): Because the top of faith is saying “No God but Allah”.
(… وَيَغْفِرُ مَا دُونَ ذَٰلِكَ لِمَن يَشَاءُ …) (…, but He forgives what is less than that for whom He wills …): The human should not despair of the mercy of Allah (swt) whatever the sins he does:
قُلْ يَا عِبَادِيَ الَّذِينَ أَسْرَفُوا عَلَىٰ أَنفُسِهِمْ لَا تَقْنَطُوا مِن رَّحْمَةِ اللَّهِ ۚ إِنَّ اللَّهَ يَغْفِرُ الذُّنُوبَ جَمِيعًا ۚ إِنَّهُ هُوَ الْغَفُورُ الرَّحِيمُ
(Say, “O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.”) (Az-Zumar: 53)
Allah (swt) is near, responds to the invocation of the supplicant, in one condition that he intends not to recommit the sin. It is narrated that abul Asswad Ad-Delli said that Abo Thar (may Allah be pleased with him) said to him:
“I came to the Prophet and found him asleep under a white sheet. When I came back to him after he had awakened, he said:
“If anyone says there is no god but God and dies in that belief, he will enter paradise.”
I asked, “Even if he commits fornication and even if he steals?” He replied:
“Even if he commits fornication and even if he steals.”
I asked, “Even if he commits fornication and even if he steals?” He replied:
“Even if he commits fornication and even if he steals.”
I asked, “Even if he commits fornication and even if he steals?” He replied:
“Even if he commits fornication and even if he steals, in spite of Abu Dharr.”
When Abu Dharr told this he said, “Even if Abu Dharr’s pride is humbled.”[2]
Meaning, if anyone committed such sins then he repents, Allah (swt) accepts his repentance. The door of repentance is open, so no person becomes strict and makes himself a judge over people for their actions and deeds. Allah (swt) is The Lord of all people:
الْحَمْدُ لِلَّهِ رَبِّ الْعَالَمِينَ
([All] praise is [due] to Allah, Lord of the worlds) (Al-Fatiha: 2)
وَمَا أَرْسَلْنَاكَ إِلَّا رَحْمَةً لِّلْعَالَمِينَ
(And We have not sent you, [O Muhammad], except as a mercy to the worlds.) (Al-Anbiyaa: 107)
( وَمَن يُشْرِكْ بِاللَّهِ فَقَدِ افْتَرَىٰ إِثْمًا عَظِيمًا … ) (…And he who associates others with Allah has certainly fabricated a tremendous sin): Whoever sets up partners with Allah (swt) in worship, he has indeed invented a tremendous sin, with which there is no repentance unless he returns to faith
[1] Sahih Ibn Hayyan: Book of Faith, Hadith No.169.
[2] Sahih Al-Bukhari, Book of Dress, Chapter of the white dress, Hadith No.5489.