Why was the conflict between the clergy and the third estate the most divisive in the course of the revolution

The 1st estate, consist of the Church/clergy. The clergy owned about 10% of France's land for which the paid no taxes and they also collected tithes from the people. The third estate is composed of the bourgeoisie, sans-culottes and the peasants. These people suffered if the state increase the taxes. Increase in taxes was commonly observed throughout the 18th century, this was due to french losing much of its colonies and the unnecessary wars waged by the previous monarchs. The rise of the thinkers like Voltaire encouraged the people to fight for their rights as a respectable human being.