Imitation of Christ

Duabus alis homo sublevatur a terrenis, scilicet simplicitate et puritate. Simplicitas debet esse in intentione, puritas in affectione. Simplicitas intendit deum, puritas apprehendit et gustat. Nulla actio te impediet, si liber intus ab omni inordinato affectu fueris. Si nihil aliud quam Dei beneplacitum, et proximi utilitatem intendis et quæris, interna libertate frueris. Si rectum cor tuum esset, tunc omnis creatura speculum vitæ, et liber sanctæ doctrinæ esset. Non est creatura tam parva et vilis quæ bonitatem Dei non repræsentet. 

By two wings is man lifted above earthly things, even by simplicity and purity. Simplicity ought to be in the intention, purity in the affection. Simplicity reaches towards God, purity apprehends Him and tastes Him. No good action will be distasteful to you if you are free within from inordinate affection. If you reach after and seek, nothing but the will of God and the benefit of your neighbor, you will entirely enjoy inward liberty. If your heart is right, then every creature should be a mirror of life and a book of holy doctrine. There is no creature so small and vile but that it shows us the goodness of God.

Imitation of Christ, II, 4:1