Constant dripping hollows out a stone. - Titus Lucretius Carus
Nothing surely is as potent as a law that may not be disobeyed. It has the force of the water drop that hollows the stone. A small dainty task, if it be really daily, will beat the labours of a spasmodic Hercules. - Anthony Trollope
Trauma ruptures and hollows. Compassion mends and fills; love heals. - Na'ama Yehuda
Dripping water hollows out stone, not through force but through persistence. - Ovid