The Great Commentary of Cornelius a Lapide: S. Luke
Ver. 3. — And he came into all the country about Jordan , preaching the baptism of repentance (i.e., stirring them up to do penance) for the remission of sins — to be obtained in the baptism of Christ. John was preaching penance, that by it they might dispose themselves for the reception of pardon and grace from Christ. See Matt. iii.
Ver. 4. — As it is written in the book of the words of Esaias the prophet , saying, The voice of one crying in the wilderness , Prepare ye the way of the Lord , make His paths straight.
Ver. 5. — Every valley shall be filled , and every mountain and hill shall be brought low ; and the crooked shall be made straight , and the rough ways shall be made smooth. S. Gregory (Hom. xx. In Evangel.), S. Augustine, S. Chrysostom, Bede, and others interpret these words as meaning, Every one that exalteth himself shall be humbled, and he that humbleth himself shall be exalted, as Christ said. This, however, is a discourse in which John exhorts his hearers to a change of life and conversation, as though he said, O ye Jews, prepare the way for Christ, your Messiah, now about to come to you. Wherefore, “ Every valley shall be filled,” i.e., let it be filled up, “ and every mountain and hill shall be brought low,” i.e., let it be brought low, “and the crooked,” i.e., difficult ways, “ shall be,” i.e ., let them be made, “ into straight,” &c. In other words, smooth all the ways for Christ, your King, Who cometh, as is wont to be done for kings that are about to enter upon their kingdoms, so that the rough ways be made smooth and level. Remove from your minds all that is evil, distorted, or unequal ; too much lifted up, or too much cast down ; he that beareth in his heart the mountain of pride, let him bring down this swelling, and he that hath in him the valley of pusillanimity or sloth, let him lift and fill it up with generosity and confidence in God ; and he that is of “ rough ” behaviour, let him train himself to suavity and modesty.
And all flesh shall see the salvation of God — i.e., so shall it come to pass that every man shall be able to see both with the eyes of the body, and also more especially with those of the soul, “the salvation of God” — the Saviour Christ — feel and experience within himself the salvation and the power of the grace brought by Christ.
S. Gregory (Hom. 20 in Evang.) says, “Every valley shall be filled up, because the humble receive a gift which the hearts of them that are puffed up repel from them. The bad places are made straight when the hearts of the wicked, turned awry by iniquity, are directed by the rule of justice; and the rough places are turned into smooth ways when haughty and angry minds return to the gentleness of meekness by the infusion of heavenly grace.”
The verses from 7 to 10 have been explained in the Commentary on S. Matthew iii. 7.
Ver. 10. — And the people asked Him , saying, What shall we do then? that we may bear fruits worthy of penance, and so avoid the ruin threatened by you, and obtain everlasting salvation. John had accused the Pharisees and the populace, but the Pharisees “ despised the counsel of God,” c. vii. 30, and therefore also the discourse of John ; but the crowd of common people, deeply moved and touched by the force of his preaching, try to find out the way to repent, so as to seize upon John’s instructions, and offer themselves to him ready and prepared. So also, in these days, the common people were more ready than the great to take hold of the warnings of preachers, and are therefore saved rather than they.
Ver. 11. — He answereth and saith unto them, He that hath two coats , let him impart to him that hath none ; and he that hath meat , let him do likewise. A synecdoche ; he signifies every kind of alms-deed by one which is the more common and necessary ; clothing and feeding the poor. “ Two,” supposing one coat to be sufficient to clothe and warm the body, and the other, therefore, superfluous, let him give that other " to him that hath not,” to him that is naked and in need of a coat. For if both be necessary he is not bound to give either to the poor man. So S. Jerome (Quaest. 1 ad Hedibiam), and S. Ambrose, on this passage, says, “ The limits of mercy are observed according to the capability of human nature, so that each one deprive not himself of everything, but share what he has with the poor man,” and he adds, “ He that is able, let him bear the fruit of grace, he that is bound, of penance. The use of mercy is common, therefore the precept is common ; mercy is the fulness of the virtues.”
This, then, is one of the fruits worthy of penance, according to the words of Daniel to Nebuchadnezzar, “ Break off thy sins by righteousness and thine iniquities by showing mercy to the poor” iv. 27.
Besides, almsgiving fitly disposes our lives for every virtue. Every virtue is either of obligation or of supererogation ; justice is of obligation , mercy of supererogation, and therefore mercy satisfies both for itself and for justice, both because he that gives what is his own, will not seize what belongs to others, and also because he that gives what he is not bound to give will much more pay what he owes — to which he is bound by justice or some other virtue — and again because mercy comes of love and charity, and charity is the fulness of the law. For “ He that loveth hath fulfilled the law,” Rom. xiii. 8.
Euthymius aptly remarks here, “ He enjoins on the multitudes to take one another into mutual benevolence, and assist one another with mutual good works.” For the many easily understand works of mercy, and devote themselves to them, while they are not easily induced to prayer, fasting, and works of penance, and sometimes are incapable of them.
Ver. 12. — Then came also publicans to be baptized , and said unto him , Master , what shall we do? — to save our souls. Here is fulfilled the saying of Christ, “ Publicans and harlots shall be before you (O Scribes) in the kingdom of God,” Matt. xxi. 31. For the sinners, being called to account by John, felt deep compunction, acknowledged their fault, and sought for penance; but the proud Scribes, thinking themselves just and wise, despised it.
Ver. 13. — And he said unto them, Exact no more than that which is appointed you — in the exaction of taxes. In the Greek it is πράσσετε, which can be translated both make and exact , but in this place is more clearly rendered exact as the Syriac and the Greek render it. So Jansenius, Maldonatus, Francis Lucas, and others. For tax-gatherers are wont to increase the tribute out of avarice, and to exact more than is appointed by the Ruler, which is theft or rapine, wherefore John here charges them with it. “He lays a moderate command on them,” says S. Augustine (Serm. 3 de Diversis), “ that both iniquity may have no place, and the appointed tribute may have effect.” “So the Baptist,” says S. Ambrose, “gives to each generation of men the answer suitable to them.” Let the preacher do the same, and prescribe to wives, to husbands, to sons, to maidservants, to menservants, to merchants, farmers, and lawyers, what each in particular ought to do, and give each one the directions proper to his state of life.