'Strive for peace with all men, and for the holiness without which no one will see the Lord' (Heb. 12:14), Why did he say 'strive'? Because it is not possible for us to become holy and to be saints in an hour! We must therefore progress from modest beginnings toward holiness and purity. Even were we to spend a thousand years in this life we should never perfectly attain it. Rather we must always struggle for it every day, as if mere beginners.

Symeon New Theologian (ed. Paulist Press, 1980) - ISBN: 9780809122301