Allah said to His faithful servants, after ordering them to be enemies with the disbelievers,

[عَسَى اللَّهُ أَن يَجْعَلَ بَيْنَكُمْ وَبَيْنَ الَّذِينَ عَادَيْتُم مِّنْهُم مَّوَدَّةً]

(Perhaps Allah will make friendship between you and those, whom you hold as enemies.) meaning affection after animosity, tenderness after coldness and coming together after parting from each other,

[وَاللَّهُ قَدِيرٌ]

(And Allah has power (over all things),) Allah is able to gather opposites and bring together hearts, after feeling hostility and hardness. In this case, the hearts will come together in agreement, just as Allah said when He mentioned His favor on the Ansar,

[وَاذْكُرُواْ نِعْمَةَ اللَّهِ عَلَيْكُمْ إِذْ كُنتُم أَعْدَآءً فَأَلَّفَ بَيْنَ قُلُوبِكُمْ فَأَصْبَحْتُم بِنِعْمَتِهِ إِخْوَاناً وَكُنتُمْ عَلَى شَفَا حُفْرَةٍ مِّنَ النَّارِ فَأَنقَذَكُمْ مِّنْهَا]

(And remember Allah's favor on you, for you were enemies one to another but He joined your hearts together, so that, by His grace, you became brethren and were on the brink of a pit of Fire, and He saved you from it.) (3:103) Also the Prophet said to them,

«أَلَمْ أَجِدْكُمْ ضُلَّالًا فَهَدَاكُمُ اللهُ بِي، وَكُنْتُمْ مُتَفَرِّقِينَ فَأَلَّفَكُمُ اللهُ بِي؟»

(Did I not find you misguided, and Allah guided you through me; and divided, and Allah united [your hearts] through me) Allah the Exalted said,

[وَإِن يُرِيدُواْ أَن يَخْدَعُوكَ فَإِنَّ حَسْبَكَ اللَّهُ هُوَ الَّذِى أَيَّدَكَ بِنَصْرِهِ وَبِالْمُؤْمِنِينَ - وَأَلَّفَ بَيْنَ قُلُوبِهِمْ لَوْ أَنفَقْتَ مَا فِى الاٌّرْضِ جَمِيعاً مَّآ أَلَّفْتَ بَيْنَ قُلُوبِهِمْ وَلَـكِنَّ اللَّهَ أَلَّفَ بَيْنَهُمْ إِنَّهُ عَزِيزٌ حَكِيمٌ ]

(He it is Who has supported you with His help and with the believers. And He has united their hearts. If you had spent all that is in the earth, you could not have united their hearts, but Allah has united them. Certainly He is Almighty, All-Wise.) (8:62,63) And in the Hadith:

«أَحْبِبْ حَبِيبَكَ هَوْنًا مَا، فَعَسَى أَنْ يَكُونَ بَغِيضَكَ يَوْمًا مَا، وَأَبْغِضْ بَغِيضَكَ هَوْنًا مَا، فَعَسَى أَنْ يَكُونَ حَبِيبَكَ يَوْمًا مَا»

(Love your loved one moderately, because one day, he might become your enemy. Hate your hated one moderately, because one day, he might become your loved one.) Allah's statement,

[وَاللَّهُ غَفُورٌ رَّحِيمٌ]

(And Allah is Oft-Forgiving, Most Merciful.) means, Allah forgives the disbelief of the disbelievers if they repent from it, returned to their Lord and surrendered to Him in Islam. Surely, He is the Oft-Forgiving, the Most-Merciful to those who repent to Him from their sins, no matter what type of the sin it is.