Matthew Poole and continuators on Leviticus 13:45

45 And the leper in whom the plague is, his clothes shall be rent , and his head bare , and he shall put a covering upon his upper lip , and shall cry, Unclean, unclean .

To wit, in the upper and former parts, which were most visible. This was done partly as a token of sorrow, Ezra 9. 3, 5. Iob 2. 12. because though this was not a sin, yet it was an effect of sin, and a sore punishment, whereby he was cut off both from converse with men, and from the enjoyment of God in his Ordinances; partly as a warning to others to keep at a due distance from him wheresoever he came; and partly, as some adde, that it might conduce to his cure by giving the freer vent to the ill humours. But the exposing of the affected part to the cold would rather hinder than further evaporation.

Another sign of mourning, as appears from Levit. 10. 6. God would have men though not overwhelmed with, yet deeply sensible of, his judgments.

Partly as another badge of his sorrow and shame, as Ezek. 24. 17, 22. Mic. 3. 7. and partly for the preservation of others from his infectious breath or touch▪

As begging the pity and prayers of others, and confessing his own infirmity, and cautioning those who came near him to keep at a distance from him.