Muwatta Imam Malik Book of Prayer in Ramadan, Hadith 2

Yahya related to me from Malik from Ibn Shihab from Abu Salama ibn Abd ar-Rahman ibn Awf from Abu Hurayra that the Messenger of Allah ﷺ used to exhort people to watch the night in prayer in Ramadan but never ordered it definitely. He used to say, "Whoever watches the night in prayer in Ramadan with trust and expectancy, will be forgiven all his previous wrong actions."
Ibn Shihab said, "The Messenger of Allah ﷺ died while that was still the custom, and it continued to be the custom in the caliphate of Abu Bakr and at the beginning of the caliphate of Umar ibn al-Khattab."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ أَبِي سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ يُرَغِّبُ فِي قِيَامِ رَمَضَانَ مِنْ غَيْرِ أَنْ يَأْمُرَ بِعَزِيمَةٍ فَيَقُولُ " مَنْ قَامَ رَمَضَانَ إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ " . قَالَ ابْنُ شِهَابٍ فَتُوُفِّيَ رَسُولُ اللَّهِ ﷺ وَالأَمْرُ عَلَى ذَلِكَ ثُمَّ كَانَ الأَمْرُ عَلَى ذَلِكَ فِي خِلاَفَةِ أَبِي بَكْرٍ وَصَدْرًا مِنْ خِلاَفَةِ عُمَرَ بْنِ الْخَطَّابِ .