Luke 9:3

This is a great vision. But if you wish to see it, remove the sandals from your feet. Remove every chain of sin. Remove the chains of the world. Leave behind earthly sandals. Jesus sent the apostles without sandals, without money, gold and silver, so that they would not carry earthly things with them. The one who seeks to do good is praised not for his sandals but for the swiftness and grace of his feet. The Scripture says, "How beautiful are the feet of those who preach the gospel of peace, of those who bring glad tidings of good things!" Therefore remove the sandals from your feet, that they may be beautiful for preaching the gospel.

(de Con. l. 2. c. 30.) Or, the Lord did not wish the disciples to possess and carry with them these things, not that they were not necessary to the support of this life, but because He sent them thus to show that these things were due to them from those believers to whom they announced the Gospel, that so they might neither possess security, nor carry about with them the necessaries of this life, either great or little. He has therefore, according to Mark, excluded all except a staff, showing that the faithful owe every thing to their ministers who require no superfluities. But this permission of the staff He has mentioned by name, when He says, They should take nothing in the way, but a staff only.

Wishing then that they should be free from the desire of wealth and the anxieties of life, He gave this injunction. He took it as a proof of their faith and courage, that when it was commanded them to lead a life of extreme poverty, they would not escape from what was ordered. For it was fitting that they should make a kind of bargain, receiving these saving virtues to recompense them for obedience to commands. And when He was making them soldiers of God, He girds them for battle against their enemies, by telling them to embrace poverty. For no soldier of God entangles himself in the affairs of a secular life. (2 Tim. 2:4.)

(Orat. ii. 69.) Now in sending His disciples to preach, our Lord enjoined many things on them, the chief of which are, that they should be so virtuous, so constant, so temperate, and, to speak briefly, so heavenly, that no less through their manner of living than their words, the teaching of the Gospel might be spread abroad. And therefore were they sent with lack of money, and staves, and a single garment; He accordingly adds, And he said to them, Take nothing in the way, neither staves.

For this reason very fitly He bade them take nothing with them, wishing them both to be free from all worldly care, and so entirely exempt from the labours that worldly things occasion, as even to pay no regard to their necessary and indispensable food. But manifestly One Who bids them abstain even from things such as these, entirely cuts away the love of riches and the desire of gain. For their glory, He said, and, so to speak, their crown, is to possess nothing. And He withdraws them even from such things as are necessary for their use, by the command to carry nothing whatsoever, neither staff, nor scrip, nor bread, nor money, nor two coats. Observe, therefore, as I said, that He withdraws them from vain distractions, and anxiety about the body, and bids them have no cares about food, repeating to them, as it were, that passage in the Psalm: "Cast thy care upon the Lord, and He shall feed thee." For true also is that which Christ said: "Ye are not able to serve God and Mammon." And again; "For where thy treasure is, there will thy heart be also." That they may lead, therefore, a consistent and simple life, and, being free from vain and superfluous anxiety, may devote themselves entirely to the duty of proclaiming His mystery, and labour without ceasing in publishing to men everywhere the tidings of salvation, He commands them to be indifferent both as regards clothing and food. And to the same effect the Saviour elsewhere spake: "For let your loins, He says, be girt, and your lights burning." But by their loins being girt, He means the readiness of the mind for every good work: and by their lights burning, that their heart be filled with divine light. […]