The most hopeful ayah in the book of Allah

Tafsir al-Ayyashi, by Muhammad b. Mas’ud al-Ayyashi, from Abu Hamza Thumali, vol 2, p.161

Once, Amir al-Mu'mineen Imam Ali (a) was sitting with some people and he asked them, "Which verse from the book of Allah gives you the most hope?"

Some of the people quoted:
إِنَّ اللّهَ لاَ يَغْفِرُ أَن يُشْرَكَ بِهِ وَيَغْفِرُ مَا دُونَ ذَلِكَ لِمَن يَشَاء وَمَن يُشْرِكْ بِاللّهِ فَقَدِ افْتَرَى إِثْمًا عَظِيمًا
"Allah does not forgive shirk but he grants forgiveness for all but that (sin) to whomever he pleases" (Surat al-Nisa). He (a) said, "That is good but it is not the one." [4:48]

Then others among them quoted,
قُلْ يَا عِبَادِيَ الَّذِينَ أَسْرَفُوا عَلَى أَنفُسِهِمْ لَا تَقْنَطُوا مِن رَّحْمَةِ اللَّهِ إِنَّ اللَّهَ يَغْفِرُ الذُّنُوبَ جَمِيعًا إِنَّهُ هُوَ الْغَفُورُ الرَّحِيمُ
"Say, O' My servants who have committed excesses against themselves! Do not despair of the mercy of Allah! Surely Allah forgives all sins..." (Surat al-Zumur). He (a) said, "That is good but it is not the one." [39:53]

Then others said that it is the aya:
وَمَن يَعْمَلْ سُوءًا أَوْ يَظْلِمْ نَفْسَهُ ثُمَّ يَسْتَغْفِرِ اللّهَ يَجِدِ اللّهَ غَفُورًا رَّحِيمًا
"Whoever does an evil deed or is unjust to himself and then does istighfaar will find Allah to be Forgiving and Merciful" (Surat al-Nisa). He (a) said, "That is good but it is not the one." [4:110]

Others said it is the aya:
وَالَّذِينَ إِذَا فَعَلُواْ فَاحِشَةً أَوْ ظَلَمُواْ أَنْفُسَهُمْ ذَكَرُواْ اللّهَ فَاسْتَغْفَرُواْ لِذُنُوبِهِمْ وَمَن يَغْفِرُ الذُّنُوبَ إِلاَّ اللّهُ وَلَمْ يُصِرُّواْ عَلَى مَا فَعَلُواْ وَهُمْ يَعْلَمُونَ
"(The pious are) those who, when they commit an evil act or are unjust to themselves, do dhikr of Allah and istighfaar for their sins. And who can forgive [literally: cover the stain of] sins except Allah?..." (Surat Aal-i-Imran) but the Imam (a) again said, "That is good but it is not the one." [3:135]

The people then fell silent and the Imam (a) asked them, "What else, O' assembly of Muslims?" They said, "Wallaah, we have nothing else to say."

He (a) said, I heard my beloved, the Messenger of Allah, say: The most hopeful ayat in the book of Allah is
وَأَقِمِ الصَّلاَةَ طَرَفَيِ النَّهَارِ وَزُلَفًا مِّنَ اللَّيْلِ إِنَّ الْحَسَنَاتِ يُذْهِبْنَ السَّـيِّئَاتِ ذَلِكَ ذِكْرَى لِلذَّاكِرِينَ
"And establish the prayers (wa aqim al-salaata) at two parts of the day and in the first part of the night. Indeed good acts wipe away evil deeds. This is but a reminder to those who are mindful" (Surat Hud, verse 114).