Numbers 5:17

And the priest shall take holy water in an earthen vessel; and of the dust that is in the floor of the tabernacle the priest shall take, and put it into the water:

Cross-references

In Numbers 5:18, the priest holds the water of bitterness — this water prepared in v.17 is now used in the ritual.

Numbers 19:2–9 Related theme

In Numbers 19:2-9, the red heifer ritual also uses holy water and ashes—both are purification rites involving water and dust.

In Leviticus 14:5, an earthen vessel with fresh water is used for cleansing lepers — similar ritual use of water and vessel here for suspected adultery.