Mark 6:9

But be shod with sandals
Which were different from shoes, and more fit to travel with, and therefore allowed when shoes were forbidden; (See Gill on Matthew 10:10), though some think there was no difference between shoes and sandals, and that Christ, in ( Matthew 10:10 ) , does not forbid the taking of shoes, but two pair of shoes; as not two coats, nor two staves, but one of a sort only. And

not put on two coats;
that is, at a time; an inner and an outward one, or one at one time, and another at another: they were forbid change of raiment; the reasons for it (See Gill on Matthew 10:10). From all which it appears, that as a minister of the Gospel ought not to be a worldly minded man, that minds earth and earthly things, and seeks to amass wealth and riches to himself, and preaches for filthy lucre's sake; nor to be a sensual and voluptuous man, serving his own belly, and not the Lord Jesus Christ, feeding himself, and not the flock; so neither should he be filled with worldly cares, overwhelmed in worldly business, and entangled with the affairs of this life: he ought to have his mind free from all solicitude and anxious concern, about a subsistence for himself and his, that so he may with greater and more close application attend to his ministry, to preparations for it, and the performance of it; and give up himself entirely to the word and prayer, and not have his mind distracted with other things: upon which account it is highly necessary, that the people to whom he ministers should take care, that a sufficient provision be made for him; that he may live without any anxious care and thought about such things, and his mind be more intent about the work he is called unto: and which is what our Lord chiefly designs by all this, who has ordained that they that preach the Gospel, should be comfortably provided for, and live of it; and which, as it makes for the peace of their minds that minister, it issues in the advantage of those who are ministered to.