St Symeon the New Theologian - A house left without a roof...is not only useless...

A house left without a roof through the neglect of the builder is not only useless, but brings ridicule on the builder.

Similarly, a person who has laid foundations through the practice of the commandments, and has raised walls through the acquisition of the higher virtues, remains incomplete, and an object of pity to the perfect, if he does not receive the grace of the Spirit in the form of contemplation and spiritual knowledge.

He will have been denied this grace for one of two reasons: either he has failed to repent; or, daunted by the serried ranks of the virtues as by a boundless forest, he may have overlooked one of them - one that may seem trivial to us, but is indispensable if the house of the virtues is to be completed, since without it that house cannot be roofed by the grace of the Spirit.

St Symeon the New Theologian