5 For thus it is written, my beloved, concerning Moses, that from the time the Holy One was revealed to him, he also loved holiness. And from the time he was sanctified, his wife ministered not to him. But it is thus written:— Joshua, the son of Nun, was the minister of Moses from his childhood. And of Joshua again it is thus written concerning him, that he used not to depart from the tabernacle. And the temporal tabernacle was not ministered to by a woman, because the Law did not allow women to enter the temporal tabernacle, but even when they came to pray, they used to pray at the door of the temporal tabernacle, and then turn back.
Moreover, he commanded the Priests, that at the time of their ministry they should continue in holiness, and should not know their wives. And also concerning Elijah it is thus written, that at one time he dwelt in Mount Carmel, and at another he dwelt at the brook Cherith, and was ministered to by his disciple; and because his heart was in heaven, the bird of heaven used to bring sustenance to him; and because he took upon him the likeness of the angels of heaven, those very angels brought him bread and water when he was fleeing from before Jezebel. And because he set all his thought in heaven, he was caught up in the chariot of fire to heaven, and there his dwelling-place was established for ever.
Elisha also walked in the footsteps of his Master. He used to dwell in the upper chamber of the Shunamite, and was ministered to by his disciple. For thus the Shunamite said— He is a holy Prophet of God and passes by us continually, for thus it becomes his holiness that we should make for him an upper chamber and do for him the service that is (necessary) in it. Now what was the service necessary in the upper chamber of Elisha? Clearly the bed and table and stool and lamp-stand only.
But what shall we say of John? He also used to dwell among men, and preserved his virginity honourably, and received the Spirit of God. Moreover, the blessed Apostle said concerning himself and concerning Barnabas:— Had we then not power to eat and to drink and to lead about wives with us? But it was not becoming or right.
Source: Demonstrations (New Advent)