Adam Clarke on Matthew 10:9

Provide neither gold, nor silver, nor brass, in your purses - Εις τας ξωνας υμων, in your Girdles. It is supposed that the people of the east carry their money in a fold of their girdles. This is scarcely correct: they carry it in a purse in their bosom, under their girdles. This I have often observed.

In a thousand instances an apostolic preacher, who goes to the wilderness to seek the lost sheep, will be exposed to hunger and cold, and other inconveniences; he must therefore resign himself to God, depending on his providence for the necessaries of life. If God have sent him, he is bound to support him, and will do it: anxiety therefore, in him, is a double crime, as it insinuates a bad opinion of the Master who has employed him. Every missionary should make himself master of this subject.

Have no money in your purse, is a command, obedience to which was secured by the narrow circumstances of most of the primitive genuine preachers of the Gospel. Whole herds of friars mendicants have professed the same principle, and abandoned themselves to voluntary poverty; but if the money be in the heart it is a worse evil. In the former case, it may be a temptation to sin; in the latter, it must be ruinous.