A Deep Piercing

Unde praedicator egregius, cum loquens subtiliter diceret: Vivus est sermo Dei et efficax, et penetrabilior omni gladio ancipiti, et pertingens usque ad divisionem animae ac spiritus illico subjunxit: Compagum quoque et medullarum, et discretor cogitationum et intentionum cordis. Distinguit enim Dei sermo compages et medullas, quia discernit cogitationes et intentiones cordis. Per compages quippe ossibus ossa junguntur. Et saepe dum quid recta cogitatione agimus, sed subito in laudis amorem declinamus, atque hoc pro laude facimus quod prius facere pro veritate coeperamus, quia cogitationes cogitationibus adjunguntur, quasi quaedam in spiritu compages fiunt. Sed habent ossa, quae in compage juncta sunt, etiam medullas. Quod praedicator sanctus apertius intulit, cum subjunxit: Discretor cogitationum et intentionum cordis. Compages enim nostrae cogitationes sunt, medullae autem intentiones. Et saepe aliud cogitamus, atque aliud est quod per cogitationem intendimus. Nam si quis proposito nummorum praemio pupilli vel viduae causam defendat, et, fortasse Ecclesiam ingrediens, in suis precibus Deo dicat: Tu vides quia causam pupilli et viduae defendo, iste procul dubio quod cogitat scit, sed quo intendat ejus cogitatio ignorat. Aliud quippe cogitat, atque alio intendit. Non enim defensionem pupilli vel viduae, sed mercedem nummorum quaerit. Nam tolle temporale praemium, et pupillum ac viduam non defendit. Sermo itaque Dei discretor est cogitationum et intentionum cordis, quia non aspicit quid apud temetipsum cogitas, sed per medullam compagis, id est per intentionem cogitationis quid accipere requiras. Sanctus Gregorius Magnus, In Ezechielem Prophetam, Liber Secundus, Homilia IX Source: Migne PL 76.1053c-1054a

The word of God is living and active, even sharper than any two edged sword, and it pierces even to the division of soul and spirit, even to joints and marrow, and it discerns between the thoughts and the intentions of the heart. 1 The word of God distinguishes between joints and marrow since it discerns between the thoughts and the intentions of the heart. Bones are joined to bones by joints, and often while we think rightly, yet suddenly we decline from love to praise, and we do for praise what we began to do for truth, because thoughts to thoughts are joined, as if by certain joints in the spirit. But these bones, which by joints are joined, also have a marrow. Which the holy preacher openly brings forth when he adds, 'and it discerns between the thoughts and the intentions of the heart.' For the joints are our thoughts and the marrow is the intent of our heart. And often we think one thing, and we intend something else with the thought. For if someone for the promise of a payment of money defends the cause of a widow or an orphan, and perhaps he enters a church, and in his prayers he says to God, 'You see that I am defending the cause of the orphan and the widow,' this is without doubt what he thinks he knows, but his thought is ignorant of his intent. He thinks one thing and he intends another. For it is not the defence of the orphan or the widow but money he seeks. Take away the temporal reward, and he does not defend the orphan and the widow. Thus the word of the Lord discerns between the thoughts and the intentions of the heart, because it does not look to what you think about yourself, but to the marrow of the joint, that is, to the intent of the thought, what it is that you seek to gain. Saint Gregory the Great, On the Prophet Ezekiel, Book 2, from Homily 9 1 Heb 4.12