Is it true that the Messenger of Allah, may Allah's peace and blessings be upon him, combined 68 prayers without any excuse?

It has not been established that the Prophet, peace and blessings be upon him, combined prayers for no excuse for this number (of times). Rather, he combined prayers while traveling, and once while in residence, not due to rain or fear. There are interpretations for this combining (of prayers) from the scholars. Combining prayers is permissible for illness, for rain that causes harm, and for fear.