18 In like manner, the other pains and hardships of life will have no end or cessation on earth; for the consequences of sin are bitter and hard to bear, and they must accompany man so long as life lasts. To suffer and to endure, therefore, is the lot of humanity; let them strive as they may, no strength and no artifice will ever succeed in banishing from human life the ills and troubles which beset it. If any there are who pretend differently - who hold out to a hard-pressed people the boon of freedom from pain and trouble, an undisturbed repose, and constant enjoyment - they delude the people and impose upon them, and their lying promises will only one day bring forth evils worse than the present. Nothing is more useful than to look upon the world as it really is, and at the same time to seek elsewhere, as We have said, for the solace to its troubles.
Source: Rerum Novarum (Vatican.va)