John Cassian: The Institutes, Book 4

Here's a little illustration of what "love" could mean in the fourth century:

Now I shall relate a deed of Abba Patermutus that is worthy of remebrance. He, desiring to renounce this world, persisted in keeping watch outside the monastery until, thanks to his unwavering perserverance and against every custom of the cenobia, he was called an received along with his young son, who was about eight years old. And when they were at last taken in, they were at once not only handed over to different superiors but even made to live in separate cells, lest the father think, from constantly seeing the lad, that, of all the goods and carnal feelings of his that he had renounced and cast aside, at least his son was still his. Thus, just as he knew that he was no longer a rich man, so he might also know that he was not a father. (bk. 4, ch. XXVII.1, p. 92)

That's not enough, though:

In order to find out more clearly whether he made more of his feeling for his kindred and of his own heart's love or of obedience and mortification in Christ (which every renunciant ought to prefer out of love for him), the little boy was purposely neglected, clothed in rags rather than garments, and so covered over and marred with filth as to shock rather than delight his father whenever he would see him. He was also exposed to the blows and slaps of different persons, which he often with his own eyes saw inflicted even arbitrarily on the innocent youngster, such that whenever he saw his cheeks they were streaked with the dirty traces of tears. And although the child was treated this was under his eyes day after day, the father's heart nonetheless remained ever stern and unmoved out of love for Christ and by the virtue of obedience. For he no longer considered as his son the child whom he had offered to Christ along with himself, nor did he worry about his present sufferings; instead he rejoiced because he saw that they were not being borne fruitlessly, and, concerned about his own humility and perfection, he gave little thought to his tears. (ch. XXVII.2–3, pp. 92–93)

You probably thought the "rejoice" was the climax of this story. You were wrong:

The elder of the cenobium, on noticing the steadfastness of his mind and his unmoving sternness, and with a view to testing his strength of mind to the utmost, made believe that he was upset with the child when one day he saw him crying, and ordered his father to take him and throw him into the river. Thereupon, as if he had been ordered to do so by the Lord, he immediately ran, took his son in his own arms and brought him to the edge of the river, intending to hurl him in. Given the fervor of his faith and obedience this would certainly have been brought to a bitter end were there not brothers purposely stationed by the back of the river, carefully watching, who somehow snatched the child from the currecnt when he had been thrown in and prevented the command, which had been fulfilled by the obedient devotion of the father, from being carried out with all its consequences. (ch. XXVII.3–4)

The other monks recognize this event as an reenactment of Abraham's almost-sacrifice of his son and afterwards hold the father in high esteem. (When the old "Abba" dies, he is appointed as his successor.)

John Cassian tells quite a few stories of this sort in his Institutes, a book in which he reconstructs from memory the practices and rules of the ascetic Christian cults he visited in Egypt as a young man. Common to all of these are the theme of striving for an extreme, self-negating obedience, sometimes bordering on the (absurdly) comical.

In one story, for instance, a monk later known as John the Dwarf is commanded to water a dry stick so that it can take root. He does so dutifully and unquestioningly for an entire year until his elder decides the game is over, pulls up the stick and looks at it, then throws it away (ch. XXIV.2–4, pp. 90–91). Cassian seems to delight in this display of a lack of independent will:

And so the youth, trained every day in exercises of this kind, matured in the virtue of obedience and shone with the grace of humility, and the sweet odor of his obedience spread through the monasteries. (ch. XXV, p. 91)

The sadomasochist vibe is not out of character. We are often told that the various religious men are "inflamed" with an "ardent desire for humility" and the like (e.g., ch. XXXI, p. 96), and there is a clear sense that there is a kind of competition going on to be most self-abnegating, most humble, most lowly, and most poor.

This has, of course, the paradoxical effect of making the lack of pride be itself a point of pride. One wins the greatest honor by heading straight for the bottom of society.