The Shepherd's Watch

Pastorum est vigilare super gregem propter tria necessaria: videlicet ad disciplinam, ad custodiam, ad preces. Ad disciplinam, propter morum correctionem, ne grex commissus propria molestia deficiat. Ad custodiam, propter diabolicam suggestionem, ne hostili seducatur calliditate. Ad preces, propter tentationum instantiam, ne vincatur a pusillanimitate. in discplina rigor justitiae, in custodia spiritus consilii, in prece affectus compassionis. Sanctus Bernardus Clarae Vallensis, Sententiae Source: Migne PL 183.750a-b

It is for shepherds to watch over the flock for three reasons: for discipline, for guarding, for prayers. For discipline on account of the correction of morals, lest the flock committed to one perish by its own troubles. For guarding on account of the temptation of the devil, lest it be seduced by malevolent cleverness. For prayers on account of present trials, lest it be overthrown by weakness. In discipline is the rigour of justice, in guarding the spirit of counsel, in prayer compassion. Saint Bernard of Clairvaux, Sentences