Thus shall ye {l} separate the children of Israel from their uncleanness; that they die not in their uncleanness, when they defile my tabernacle that is among them.

(l) Seeing that God required purity and cleanliness of his own: we cannot be his, unless our filth and sins are purged with the blood of Jesus Christ, and so we learn to detest all sin.

Wesley's Notes

15:31 When they defile my tabernacle - Both ceremonially, by coming into it in their uncleanness, and morally by the contempt of God's express command to cleanse themselves. The grand reason of all these laws was, to separate the children of Israel from their uncleanness. Hereby they were taught their privilege and honour, that they were purified unto God, a peculiar people; for that was a defilement to them, which was not so to others. They were also taught their duty, which was to keep themselves clean from all pollutions.

Jamieson-Fausset-Brown Bible Commentary

31-33. Thus shall ye separate the children of Israel from their uncleanness-The divine wisdom was manifested in inspiring the Israelites with a profound reverence for holy things; and nothing was more suited to this purpose than to debar from the tabernacle all who were polluted by any kind of uncleanness, ceremonial as well as natural, mental as well as physical. The better to mark out that people as His family, His servants and priests, dwelling in the camp as in a holy place, consecrated by His presence and His tabernacle, He required of them complete purity, and did not allow them to come before Him when defiled, even by involuntary or secret impurities, as a want of respect due to His majesty. And when we bear in mind that God was training a people to live in His presence in some measure as priests devoted to His service, we shall not consider these rules for the maintenance of personal purity either too stringent or too minute (1Th 4:4).

Matthew Henry's Concise Commentary

15:1-33 Laws concerning ceremonial uncleanness. - We need not be curious in explaining these laws; but have reason to be thankful that we need fear no defilement, except that of sin, nor need ceremonial and burdensome purifications. These laws remind us that God sees all things, even those which escape the notice of men. The great gospel duties of faith and repentance are here signified, and the great gospel privileges of the application of Christ's blood to our souls for our justification, and his grace for our sanctification.