Objection 1. It would seem that Christ should not have led a life of poverty in this world. Because Christ should have embraced the most eligible form of life. But the most eligible form of life is that which is a mean between riches and poverty; for it is written (Proverbs 30:8): "Give me neither beggary nor riches; give me only the necessaries of life." Therefore Christ should have led a life, not of poverty, but of moderation.
Objection 2. Further, external wealth is ordained to bodily use as to food and raiment. But Christ conformed His manner of life to those among whom He lived, in the matter of food and raiment. Therefore it seems that He should have observed the ordinary manner of life as to riches and poverty, and have avoided extreme poverty.
Objection 3. Further, Christ specially invited men to imitate His example of humility, according to Matthew 11:29: "Learn of Me, because I am meek and humble of heart." But humility is most commendable in the rich; thus it is written (1 Timothy 6:11): "Charge the rich of this world not to be high-minded." Therefore it seems that Christ should not have chosen a life of poverty.
On the contrary, It is written (Matthew 8:20): "The Son of Man hath not where to lay His head": as though He were to say as Jerome observes: "Why desirest thou to follow Me for the sake of riches and worldly gain, since I am so poor that I have not even the smallest dwelling-place, and I am sheltered by a roof that is not Mine?" And on Matthew 17:26: "That we may not scandalize them, go to the sea," Jerome says: "This incident, taken literally, affords edification to those who hear it when they are told that our Lord was so poor that He had not the wherewithal to pay the tax for Himself and His apostles."
I answer that, It was fitting for Christ to lead a life of poverty in this world. First, because this was in keeping with the duty of preaching, for which purpose He says that He came (Mark 1:38): "Let us go into the neighboring towns and cities, that I may preach there also: for to this purpose am I come." Now in order that the preachers of God's word may be able to give all their time to preaching, they must be wholly free from care of worldly matters: which is impossible for those who are possessed of wealth. Wherefore the Lord Himself, when sending the apostles to preach, said to them (Matthew 10:9): "Do not possess gold nor silver." And the apostles (Acts 6:2) say: "It is not reasonable that we should leave the word of God and serve tables."
Secondly, because just as He took upon Himself the death of the body in order to bestow spiritual life on us, so did He bear bodily poverty, in order to enrich us spiritually, according to 2 Corinthians 8:9: "You know the grace of our Lord Jesus Christ: that... He became poor for our [Vulgate: 'your'] sakes that through His poverty we [Vulgate: 'you'] might be rich."
Thirdly, lest if He were rich His preaching might be ascribed to cupidity. Wherefore Jerome says on Matthew 10:9, that if the disciples had been possessed of wealth, "they had seemed to preach for gain, not for the salvation of mankind." And the same reason applies to Christ.
Fourthly, that the more lowly He seemed by reason of His poverty, the greater might the power of His Godhead be shown to be. Hence in a sermon of the Council of Ephesus (P. iii, c. ix) we read: "He chose all that was poor and despicable, all that was of small account and hidden from the majority, that we might recognize His Godhead to have transformed the terrestrial sphere. For this reason did He choose a poor maid for His Mother, a poorer birthplace; for this reason did He live in want. Learn this from the manger."
Reply to Objection 1. Those who wish to live virtuously need to avoid abundance of riches and beggary, in as far as these are occasions of sin: since abundance of riches is an occasion for being proud; and beggary is an occasion of thieving and lying, or even of perjury. But forasmuch as Christ was incapable of sin, He had not the same motive as Solomon for avoiding these things. Yet neither is every kind of beggary an occasion of theft and perjury, as Solomon seems to add (Proverbs 30:8); but only that which is involuntary, in order to avoid which, a man is guilty of theft and perjury. But voluntary poverty is not open to this danger: and such was the poverty chosen by Christ.
Reply to Objection 2. A man may feed and clothe himself in conformity with others, not only by possessing riches, but also by receiving the necessaries of life from those who are rich. This is what happened in regard to Christ: for it is written (Luke 8:2-3) that certain women followed Christ and "ministered unto Him of their substance." For, as Jerome says on Matthew 27:55, "It was a Jewish custom, nor was it thought wrong for women, following the ancient tradition of their nation, out of their private means to provide their instructors with food and clothing. But as this might give scandal to the heathens, Paul says that he gave it up": thus it was possible for them to be fed out of a common fund, but not to possess wealth, without their duty of preaching being hindered by anxiety.
Reply to Objection 3. Humility is not much to be praised in one who is poor of necessity. But in one who, like Christ, is poor willingly, poverty itself is a sign of very great humility.
Source: Summa Theologica (New Advent)