Sa'id bin Jubayr (may Allah have mercy on him) narrates from Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) combined Zuhr, Asr, Maghrib and Isha in Madinah without any fear or journey. I said: O Ibn Abbas, what was his (peace and blessings be upon him) intention? He said: So that his (peace and blessings be upon him) Ummah would not be put in hardship.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5548