حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، حَدَّثَنَا وَكِيعٌ، عَنْ سُفْيَانَ، عَنْ سَلَمَةَ بْنِ كُهَيْلٍ، عَنِ الْقَاسِمِ بْنِ مُخَيْمِرَةَ، عَنْ أَبِي عَمَّارٍ، عَنْ قَيْسِ بْنِ سَعْدٍ، قَالَ أَمَرَنَا رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ بِصَدَقَةِ الْفِطْرِ قَبْلَ أَنْ تُنْزَلَ الزَّكَاةُ فَلَمَّا نَزَلَتِ الزَّكَاةُ لَمْ يَأْمُرْنَا وَلَمْ يَنْهَنَا وَنَحْنُ نَفْعَلُهُ ‏.‏

It was narrated that: Qais bin Sa'ad said: “The Messenger of Allah (PBUH) enjoined Sadaqatul-Fitr upon is before (the command of) Zakat was revealed. He neither ordered us (to pay) nor forbade us (from paying it), so we did it.” Translation Not Available

Book Ref: Sunan Ibn Majah Book 8 Hadith 1828
Web Ref:  Sunan Ibn Majah Vol 3 Book 8 Hadith 1828