You should take care always to be inclined to the difficult more than to the easy, to the rugged more than to the soft, to the hard and distasteful in a work more than to its delightful and pleasant aspects; and do not go about choosing what is less of a cross, for the cross is a light burden (Matt. 11:30). The heavier a burden is, the lighter it becomes when borne for Christ.
St John of the Cross
Counsels to a Religious, 6
John of the Cross, St 1991, The Collected Works of St. John of the Cross, translated from the Spanish by Kavanaugh, K and Rodriguez, O, ICS Publications, Washington DC.