Musnad Ahmad 33:607

Musa narrated to us, Ibn Lahi'ah narrated to us, from Abu al-Zubayr, from Jabir, that he heard the Prophet, peace and blessings of Allah be upon him, saying: "I hope that those who follow me from my nation on the Day of Resurrection will be a quarter of the people of Paradise." He said: So we said 'Allahu Akbar' (God is the Greatest). Then he said: "I hope that they will be a third of the people." He said: So we said 'Allahu Akbar'. Then he said: "I hope that they will be half."