Complete Commentary on the Whole Bible, by Matthew Henry, at sacred-texts.com
(Deu 19:1-13) The cities of refuge, The man-slayer, The murderer.
(Deu 19:14) Landmarks not to be removed.
(Deu 19:15-21) The punishment of false witnesses.
Here is the law settled between the blood of the murdered, and the blood of the murderer; provision is made, that the cities of refuge should be a protection, so that a man should not die for that as a crime, which was not his willing act. In Christ, the Lord our Righteousness, refuge is provided for those who by faith flee unto him. But there is no refuge in Jesus Christ for presumptuous sinners, who go on still in their trespasses. Those who flee to Christ from their sins, shall be safe in him, but not those who expect to be sheltered by him in their sins.
Direction is given to fix landmarks in Canaan. It is the will of God that every one should know his own; and that means should be used to hinder the doing and suffering of wrong. This, without doubt, is a moral precept, and still binding. Let every man be content with his own lot, and be just to his neighbours in all things.
Sentence should never be passed upon the testimony of one witness alone. A false witness should suffer the same punishment which he sought to have inflicted upon the person he accused. Nor could any law be more just. Let all Christians not only be cautious in bearing witness in public, but be careful not to join in private slanders; and let all whose consciences accuse them of crime, without delay flee for refuge to the hope set before them in Jesus Christ.