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Surah 6. Al-An'am
Ayah 54 - 55
54وَإِذَا جَآءَكَ ٱلَّذِينَ يُؤْمِنُونَ بِـَٔايَـٰتِنَا فَقُلْ سَلَـٰمٌ عَلَيْكُمْ ۖ كَتَبَ رَبُّكُمْ عَلَىٰ نَفْسِهِ ٱلرَّحْمَةَ ۖ أَنَّهُۥ مَنْ عَمِلَ مِنكُمْ سُوٓءًۢا بِجَهَـٰلَةٍ ثُمَّ تَابَ مِنۢ بَعْدِهِۦ وَأَصْلَحَ فَأَنَّهُۥ غَفُورٌ رَّحِيمٌ
55وَكَذَٰلِكَ نُفَصِّلُ ٱلْـَٔايَـٰتِ وَلِتَسْتَبِينَ سَبِيلُ ٱلْمُجْرِمِينَ
[54-55] When those, who have believed in Our Revelations, come to you, say to them, "Peace be upon you: your Lord has prescribed for Himself mercy and compassion. (It is His compassion that) He forgives and treats with leniency anyone who commits an evil through ignorance and then repents and mends his ways."37 In this way, We make Our Signs clear and plain so as to expose the way of the guilty ones.38
37Allah has told his Messenger to console those of His followers who had committed heinous sins during the days of "ignorance" by inspiring them with the assurance that He forgives and treats leniently those who repent and mend their ways and, therefore, the taunts of the enemies of Islam need not worry them about what they had done in the past.
38In order to understand the significance of v. 55, we should keep in view v. 37 in which the disbelievers asked, "Why has no Sign been sent down to this Prophet from his Lord?" In the subsequent passage (vv. 38-54) several manifest Signs have been cited to show that there is no lack of Signs but the disbelievers do not want to see them. Then in v. 55 such people have been warned, as if to say, "In this way We make Our Signs clear, plain and manifest so that those, who persist in their disbelief inspire of those Signs, should prove themselves to be guilty ones. For they choose the way of deviation deliberately, not because there is a lack of Signs to show the Right Way but because they do not want to see the Signs."