Numbers 19:12 He shall purify himself with it on the third day, and on the seventh day he shall be clean: but if he purify not himself the third day, then the seventh day he shall not be clean.
Sin defiles. The blood of Christ cleanses. God calls us to cleanse ourselves from all filthiness and live a holy life through the washing of His Word. These truths expounded in the New Testament (1 Cor 6:14-7:1, Eph 5:25-27, 1 John 1:5-2:2) are illustrated by the sacrifice of the red heifer. This heifer was killed; its blood was sprinkled before the tabernacle; then its ashes were used to form a type of cleansing agent for them to use when they became defiled.
The shed blood of Christ is the foundation of all cleansing. And the application of that cleansing is not just in atoning for our sins but also in daily, practical cleansing from the defilement of sin. As we get into God’s Word, the truths of the cross and the work of Christ help to cleanse away the impurities that come through contact with the world.
2 Corinthians 7:1 Having therefore these promises, dearly beloved, let us cleanse ourselves from all filthiness of the flesh and spirit, perfecting holiness in the fear of God.
John 15:3 Now ye are clean through the word which I have spoken unto you.