Maximus the Confessor

Which it is said is come nigh, not to show the shortness of time, for the kingdom of God cometh not with observation, but to mark the disposition of men towards the kingdom of God, which is indeed potentially in all believers, but actually in those who reject the life of the body, and choose only the spiritual life; who are able to say, Now I live, yet not I, but Christ liveth in me. (Gal. 2:20.)

Catena Aurea by Aquinas ↗

Theophylact of Ohrid

Here someone will ask: how does the Lord say that the Kingdom of God has drawn near both to those who receive the apostles and to those who do not receive them? It must be said that He in no way contradicts Himself. For to those who receive the apostles, the Kingdom draws near with benefactions, and to those who do not receive them, with condemnation. …

Commentary on Luke ↗

Bede

Either as a testimony to the earthly toil which they had in vain undergone for them, or to show that so far from seeking any thing earthly from them, they suffer not even the dust from their land to cleave to them. Or by the feet is meant the very labour and walking to and fro of preaching; but the dust with which they are sprinkled is the lightness of worldly thoughts, from which even the greatest teachers cannot be free. …

Catena Aurea by Aquinas ↗

Bonaventure

Say: Even the dust from your feet that clings to us from your city, we wipe off against you, on account of contempt of the truth, which is a sin greatly to be detested, according to that passage in John 15: "If I had not come and spoken to them, they would not have sin." And therefore, for the detestation of this offense, he says the dust is to be wiped off, as Peter said to Simon in Acts 8: "May your money be with you unto destruction." Yet know this, that the kingdom of God has drawn near, that is, the truth of the Gospel, …

Commentary on Luke, Chapter 10 ↗