Gregory of Nyssa
Catena Aurea · Lukasevangelium 14
For which of you, intending to build a tower, sitteth not down first, and counteth the cost, whether he have sufficient to finish it? Lest haply, after he hath laid the foundation, and is not able to finish it, all that behold it begin to mock him, Saying, This man began to build, and was not able to finish. Or what king, going to make war against another king, sitteth not down first, and consulteth whether he be able with ten thousand to meet him that cometh against him with twenty thousand? Or else, while the other is yet a great way off, he sendeth an ambassage, and desireth conditions of peace. So likewise, whosoever he be of you that for-saketh not all that he hath, he cannot be my disciple.
(lib. de Virg. 17.) For we must be ever pressing onward that we may reach the end of each difficult undertaking by successive increases of the commandments of God, and so to the completion of the divine work. For neither is one stone the whole fabric of the tower, nor does a single command lead to the perfection of the soul. But we must lay the foundation, and according to the Apostle, thereupon must be placed store of gold, silver, and precious stones. (1 Cor. 3:12.) Whence it is added, Lest haply after he hath laid the foundation, &c.