Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
ahmad:10118ʿAbd al-Ṣamad And ʾAbū ʿĀmir > Hishām Wadhakarā > Illā Annahumā

[Machine] Hisham narrated to us and mentioned something similar to it, except that they said, "Whoever observes Ramadan in faith'".  

أحمد:١٠١١٨حَدَّثَنَا عَبْدُ الصَّمَدِ وَأَبُو عَامِرٍ قَالَا

حَدَّثَنَا هِشَامٌ وَذَكَرَا مِثْلَهُ إِلَّا أَنَّهُمَا قَالَا مَنْ قَامَ رَمَضَانَ إِيمَانًا