Imitation of Christ

Cum igitur spiritualis consolatio a Deo datur, cum gratiarum actione accipe eam et Dei munus intellige esse, et non tuum meritum et noli extolli. Noli nimium gaudere nec inaniter præsumere, sed esto magis humilior ex dono, cautior quoque et timoratior in cunctis actibus tuis, quoniam transibit hora illa, et sequetur tentatio. Cum ablata fuerit consolatio, non statim desperes, sed cum humilitate, et patientia exspecta cælestem visitationem, quia potens est Deus ampliorem tibi redonare gratiam et consolationem. Istud non est novum, nec alienum viam Dei expertis, quia in magnis sanctis, et in antiquis prophetis suit sæpe alternationis modus. 

When, therefore, spiritual comfort is given by God, receive it with giving of thanks, and know that it is the gift of God, not your desert. Be not lifted up, rejoice not overmuch nor foolishly presume, but rather be more humble for the gift, more wary and more careful in all your doings; for that hour will pass away, and temptation will follow. When comfort is taken from you, do not straightway despair, but wait for the heavenly visitation with humility and patience, for God is able to give you back greater favour and consolation. This is not new nor strange to those who have made trial of the way of God, for with the great saints and the ancient prophets there was often this manner of change.

  
Imitation of Christ, II, 9:4