Numbers 19:9

Now a man who is [ceremonially] clean shall collect the ashes of the heifer and deposit them outside the camp in a clean place, and the congregation of the Israelites shall keep it for water to remove impurity; it is [to be used for] purification from sin.

Numbers 19:13

Whoever touches a corpse, the body of anyone who has died, and does not purify himself, defiles the tabernacle of the Lord; and that person shall be cut off from Israel [that is, excluded from the atonement made for them]. Because the water for impurity was not sprinkled on him, he shall be unclean; his uncleanness is still on him.

Hebrews 9:13

For if the sprinkling of [ceremonially] defiled persons with the blood of goats and bulls and the ashes of a [burnt] heifer is sufficient for the cleansing of the body,

Numbers 19:20-21

‘But the man who is unclean and does not purify himself, that person shall be cut off from among the assembly, because he has defiled the sanctuary of the Lord. The water for purification has not been sprinkled on him; he is unclean.

Leviticus 15:20

Everything on which she lies during her menstrual impurity shall be unclean; and everything on which she sits shall be unclean.

Numbers 6:12

and he shall dedicate himself to the Lord for the time of his separation and shall bring a male lamb a year old as a guilt offering; but the previous days will be void and lost, because his separation was defiled.

Numbers 8:7

This is what you shall do to them to [ceremonially] cleanse them: sprinkle the water of purification on them, and let them use a razor over their whole body and wash their clothes, and they will be clean.

Numbers 9:13

But the man who is [ceremonially] clean and is not on a journey, and yet does not observe the Passover, that person shall be cut off from among his people [excluding him from the atonement made for them] because he did not bring the Lord’s offering at its appointed time; that man will bear [the penalty of] his sin.

Numbers 19:18

A clean person shall take hyssop and dip it in the water and sprinkle it on the tent and on all the furnishings and on the people who were there, and on the one who touched the bone or the one who was killed or the one who died [naturally] or the grave.

Numbers 31:23-24

everything that can stand fire, you shall pass through fire, and it shall be clean. Nevertheless, it shall also be purified with the water of purification [to remove its impurity]; and all that cannot stand fire [such as fabrics] you shall pass through water.

Zechariah 13:1

“In that day a fountain shall be opened for the house of David and for the people of Jerusalem for [cleansing from] sin and impurity.

2 Corinthians 5:21

He made Christ who knew no sin to [judicially] be sin on our behalf, so that in Him we would become the righteousness of God [that is, we would be made acceptable to Him and placed in a right relationship with Him by His gracious lovingkindness].

2 Corinthians 7:1

Therefore, since we have these [great and wonderful] promises, beloved, let us cleanse ourselves from everything that contaminates body and spirit, completing holiness [living a consecrated life—a life set apart for God’s purpose] in the fear of God.

Hebrews 7:26

It was fitting for us to have such a High Priest [perfectly adapted to our needs], holy, blameless, unstained [by sin], separated from sinners and exalted higher than the heavens;

Treasury of Scripture Knowledge

Summary

And a man that is clean shall gather up the ashes of the heifer, and lay them up without the camp in a clean place, and it shall be kept for the congregation of the children of Israel for a water of separation: it is a purification for sin.

Lay them up

General references

Bible References

Clean

Numbers 19:18
A clean person shall take hyssop and dip it in the water and sprinkle it on the tent and on all the furnishings and on the people who were there, and on the one who touched the bone or the one who was killed or the one who died [naturally] or the grave.
Numbers 9:13
But the man who is [ceremonially] clean and is not on a journey, and yet does not observe the Passover, that person shall be cut off from among his people [excluding him from the atonement made for them] because he did not bring the Lord’s offering at its appointed time; that man will bear [the penalty of] his sin.
2 Corinthians 5:21
He made Christ who knew no sin to [judicially] be sin on our behalf, so that in Him we would become the righteousness of God [that is, we would be made acceptable to Him and placed in a right relationship with Him by His gracious lovingkindness].
Hebrews 7:26
It was fitting for us to have such a High Priest [perfectly adapted to our needs], holy, blameless, unstained [by sin], separated from sinners and exalted higher than the heavens;
Hebrews 9:13
For if the sprinkling of [ceremonially] defiled persons with the blood of goats and bulls and the ashes of a [burnt] heifer is sufficient for the cleansing of the body,

Lay them up

Numbers 19:17
Then for the unclean person they shall take some of the ashes of the heifer burnt for the purification from sin, and running water shall be added to them in a container.

A water of separation

Leviticus 15:20
Everything on which she lies during her menstrual impurity shall be unclean; and everything on which she sits shall be unclean.
Zechariah 13:1
“In that day a fountain shall be opened for the house of David and for the people of Jerusalem for [cleansing from] sin and impurity.
2 Corinthians 7:1
Therefore, since we have these [great and wonderful] promises, beloved, let us cleanse ourselves from everything that contaminates body and spirit, completing holiness [living a consecrated life—a life set apart for God’s purpose] in the fear of God.

General references

Leviticus 22:6
the person who touches any such thing shall be unclean until evening and shall not eat the holy things unless he has bathed his body in water.
Numbers 19:18
A clean person shall take hyssop and dip it in the water and sprinkle it on the tent and on all the furnishings and on the people who were there, and on the one who touched the bone or the one who was killed or the one who died [naturally] or the grave.