وَكَذَلِكَ فَتَنَّا بَعْضَهُمْ بِبَعْضٍ لِيَقُولُوا أَهَؤُلَاءِ مَنَّ اللَّهُ عَلَيْهِمْ مِنْ بَيْنِنَا أَلَيْسَ اللَّهُ بِأَعْلَمَ بِالشَّاكِرِينَ ﴿۵۳﴾ وَإِذَا جَاءَكَ الَّذِينَ يُؤْمِنُونَ بِآيَاتِنَا فَقُلْ سَلَامٌ عَلَيْكُمْ كَتَبَ رَبُّكُمْ عَلَى نَفْسِهِ الرَّحْمَةَ أَنَّهُ مَنْ عَمِلَ مِنْكُمْ سُوءًا بِجَهَالَةٍ ثُمَّ تَابَ مِنْ بَعْدِهِ وَأَصْلَحَ فَأَنَّهُ غَفُورٌ رَحِيمٌ ﴿۵۴﴾ وَكَذَلِكَ نُفَصِّلُ الْآيَاتِ وَلِتَسْتَبِينَ سَبِيلُ الْمُجْرِمِينَ ﴿۵۵﴾ قُلْ إِنِّي نُهِيتُ أَنْ أَعْبُدَ الَّذِينَ تَدْعُونَ مِنْ دُونِ اللَّهِ قُلْ لَا أَتَّبِعُ أَهْوَاءَكُمْ قَدْ ضَلَلْتُ إِذًا وَمَا أَنَا مِنَ الْمُهْتَدِينَ ﴿۵۶﴾

﴾53﴿ Wa kazaalika fatannaa ba'dahum biba'dil liyaqoolooo ahaaa'ulaaa'i mannal laahu 'alaihim mim baininaa; alaisal laahu bi-a'lama bish shaakireen
﴾54﴿ Wa izaa jaaa'akal lazeena yu'minoona bi Aayaatinaa faqul salaamun 'alaikum kataba Rabbukum 'alaa nafsihir rahmata annahoo man 'amila minkum sooo'am bijahaalatin summa taaba mim ba'dihee wa aslaha fa annahoo Ghafoorur Raheem
﴾55﴿ Wa kazaalika nufassilul Aayaati wa litastabeena sabeelul mujrimeen
﴾56﴿ Qul innee nuheetu an a'budal lazeena tad'oona min doonil laah; qul laaa attabi'u ahwaaa'akum qad dalaltu izanw wa maaa ana minal muhtadeen

﴾53﴿ And also we always tried some to others, In the end, they say (the disbelievers) are these the ones whom Allah Almighty has bestowed upon them from among us Isn't Allah Most Wise over those who give thanks
﴾54﴿ And when those who believe in Our revelations come to you So tell them be saved you from troubles, your Lord has made it necessary for you to have mercy on yourself (He is this) Whoever has done a bad deed from you in ignorance should repent after that and do a good deed, then surely He is the Forgiving, the Merciful
﴾55﴿ And also (always) we detail the verses (of monotheism) (so that the truth is revealed) and the way of the criminals is well revealed
﴾56﴿ You say, I am prohibited from worshiping those whom you call except Allah Almighty Say: I will not follow your wishes, lest I go astray and not be among the righteous

[53] This verse speaks about one of the challenges (ʿuqabāt) in the path of conveying the message (tablīgh)—this is the first obstacle.
It means that polytheists and monotheists are a test for one another.
The first test for the believers (monotheists) is that the disbelievers object: “Has the favor of truth and righteousness been limited only to you? Are none else deserving?”
The response: Allah knows best who His true servants are.
(Ash-shākirīn) – refers to those who are truly grateful and sincere; it also clarifies the issue that Allah grants Islam to those worthy of it.
(Wa kadhālika) – the kāf here is for analogy, showing that just as in Makkah the wealthy disbelievers looked down upon the poor Muslims, this pattern repeats in every era, like in the time of Nūḥ (peace be upon him).
The phrase kadhālika implies that this type of trial is ongoing and happens continuously in different times.
(Li-yaqūlū) – the lām here is for consequence (ʿāqibah), meaning: they say this as a result of their arrogance and disbelief.
(A-hā’ulā’i) – is an interrogative of rejection and sarcasm: “Are these the ones?”—implying, “Are they truly worthy of faith and divine favor? We are more deserving!”
(Ash-shākirīn) – again, highlights that those who have the capacity for true faith, Allah grants them the tawfīq (success) to embrace Islam and be among the grateful.
[54] This verse teaches etiquette (adab)—that when the one delivering the truth faces hardship or feels humbled, he should respond to people with kind and gentle words.
When the opponents mocked the new believers, saying: “You were previously in shirk, disbelief, and sin—now you’re the ones preaching to us?”—the response is given in the form of the phrase:
(Kataba rabbukum… Salāmun ʿalaykum)
(Salāmun ʿalaykum) – here, salām is not merely a greeting, but rather a welcome and a prayer for well-being, both in religious and worldly matters.
(Annahu) – this clause explains the rahmah (mercy): that after repentance, Allah’s forgiveness is mercy itself.
Question: Normally, the one entering a gathering gives the salām, but here it appears reversed.
Answer: This is a command to convey Allah’s salām to the repentant believers—it's not a regular human-to-human greeting.
It could also mean: “May Allah grant you peace”—a du‘ā from the Prophet to them.
Or it is a special honor for the Companions (ṣaḥābah).
Or it is like saying “Marḥaban” (welcome), which in the Qur’an can come in many forms with various layers of meaning.
[55] This is the second obstacle (ʿuqbah) in the path of tablīgh (conveying the message). The disbelievers would object: “Do you not have any other topic? You always speak about this one issue—Tawḥīd (the Oneness of Allah). Are you ignorant of other matters?”
The answer is: We repeat this message because the paths of Tawḥīd and Shirk must be clearly distinguished.
It is a matter of such importance that it must be made evident again and again.
(Wa li-tastabīna) – “so that it becomes clear,” refers to the distinction between truth and falsehood.
Before this phrase, the part it is connected to (maʿṭūf ʿalayh) is omitted for brevity. The implied full meaning is:
“So that the path to the truth becomes clear to you (li-yaẓhara laka al-ḥaqq), and so that the way of the criminals becomes distinct (wa li-tastabīna sabīlu al-mujrimīn).”
This justifies the repeated emphasis on Tawḥīd: not due to lack of knowledge, but because it is the foundation upon which all truth and salvation rest.
[56] This verse also contains etiquette (adab), the method of teaching, and answers to common objections.

First question: “Why don't you worship others besides Allah? Isn't it allowed?” Answer: “I have been forbidden from doing so.” Worshiping anyone besides Allah is not a choice for a Prophet—it is absolutely prohibited.
Second question: “Why don't you follow our religion or our ways?” Answer: “That is merely following desires, which leads to misguidance and abandoning true guidance.”
The verse also explicitly mentions “sabīl al-mujrimīn”—“the way of the criminals”—which here refers to the worship of other than Allah.
So, the Prophet (May Allah bless him and give him peace) is instructed to avoid their religion because it is rooted in shirk and deviation from truth.