Luke 14:30

(in Esai. 2.) Or the tower is a lofty watch-tower fitted for the guardianship of the city and the discovery of the enemy's approach. In like manner was our understanding given us to preserve the good, to guard against the evil. For the building up whereof the Lord bids us sit down and count our means if we have sufficient to finish. But our Lord's intention in the above-mentioned example is not indeed to afford occasion or give liberty to any one to become His disciple or not, as indeed it is lawful not to begin a foundation, or not to treat of peace, but to show the impossibility of pleasing God, amidst those things which distract the soul, and in which it is in danger of becoming an easy prey to the snares and wiles of the devil.

(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.

(ut sup.) But as with respect to the unfinished tower, he alarms us by the reproaches of those who say, The man began to build, and was not able to finish, so with regard to the king with whom the battle was to be, he reproved even peace, adding, Or else, while the other is yet a great way off, he sendeth an ambassage, and desireth conditions of peace; signifying that those also who forsake all they possess cannot endure from the devil the threats of even coming temptations, and make peace with him by consenting unto him to commit sin.

(ubi sup.) For when occupied in good works, unless we watch carefully against the evil spirits, we find those our mockers who are persuading us to evil. But another comparison is added proceeding from the less to the greater, in order that from the least things the greatest may be estimated. For it follows, Or what king, going to make war against another king, sitteth not down first, and consultelh whether he be able with ten thousand to meet him that cometh against him with twenty thousand?

For we ought not to lay a foundation, i. e. begin to follow Christ, and not bring the work to an end, as those of whom St. John writes, That many of his disciples went backward. (John 6:66.) Or by the foundation understand the word of teaching, as for instance concerning abstinence. There is need therefore of the above-mentioned foundation, that the building up of our works be established, a tower of strength from the face of the enemy. (Ps. 61:3.) Otherwise, man is laughed at by those who see him, men as well as devils.