Jesus said to his disciples: “Gird your loins and light your lampsand be like servants who await their master’s return from a wedding, ready to open immediately when he comes and knocks. Blessed are those servants whom the master finds vigilant on his arrival. Amen, I say to you, he will gird himself,have them recline at table, and proceed to wait on them. And should he come in the second or third watchand find them prepared in this way,blessed are those servants."
From St. Bernard of Clairvaux, (1091-1153), Cistercian monk and doctor of the Church
Sermon 17 on the Song of Songs, 2
"We have to be vigilant and careful about the work of salvation ceaselessly performed in our inmost being with all the skill and sweetness of the Holy Spirit's artistry. If we do not wish to be deprived of a twofold gift, let us make sure that this heaven-sent Director, who can teach us all things, is never taken away from us without our knowledge.
Let him never find us unprepared when he comes, but always with faces uplifted and hearts expanded to receive the copious blessing of the Lord. Let him find us "like people who are waiting for their master to come home from the marriage-feast", for he never comes empty-handed from heaven's richly-laden table. Therefore we must keep watch, even hour by hour, for we do not know at what hour he will come and depart again.
The Holy Spirit comes and goes (Jn 3:8), and if we can stand firmly only with his support, it follows that we must fall when abandoned by him; fall, yes, but never fatally, since the Lord supports us by the hand. Persons who are spiritual or whom the Holy Spirit purposes to make spiritual, never cease to experience these alternations; he visits them every morning and tests them at any moment. "