Qudamah bin Wabarah (may Allah have mercy on him) says that the Messenger of Allah (peace and blessings be upon him) said: "Whoever misses the Friday prayer without an excuse should give a dirham, or half a dirham, or a sa' of wheat, or half a sa' in charity."
Imam Ahmad was asked about the hadith of Hammam from Qatadah and Abu al-Ala's disagreement with him in it, and he said: In our view, Hammam is a better memoriser than Ayyub Abu al-Ala'. Imam Ahmad said: Khalid bin Qays narrated it from Qatadah, agreeing with Hammam in the text of the hadith but differing from him in its chain.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجمعة / 5991