For when we despise the world, we must not imagine we have resigned any thing great, for the whole earth in comparison of the heaven is but a span long; therefore even should they who renounce it be lords of the whole earth, yet still it would be nothing worth in comparison of the kingdom of heaven.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: ex Apol. de sua fuga.