for after Moses had announced every command in the Law to all the people, he took the blood of calves and goats, together with water, scarlet wool and hyssop, sprinkling the book and all the people, and saying, This is the blood of that covenant which is God's command for you. He even sprinkled with blood the tent and all the utensils of worship in the same way. read more.
In fact, one might almost say that by Law everything is cleansed with blood. No blood shed, no remission of sins!

not taking any blood of goats and oxen but his own blood, and entered once for all into the Holy place. He secured an eternal redemption. For if the blood of goats and bulls and the ashes of a heifer, sprinkled on defiled persons, give them a holiness that bears on bodily purity, how much more shall the blood of Christ, who in the spirit of the eternal offered himself as an unblemished sacrifice to God, cleanse your conscience from dead works to serve a living God?

let us draw near with a true heart, in absolute assurance of faith, our hearts sprinkled clean from a bad conscience, and our bodies washed in pure water;

"Why do your disciples transgress the tradition of the elders? They do not wash their hands when they take their food."

They noticed that some of his disciples ate their food with 'common' (that is, unwashed) hands. (The Pharisees and all the Jews decline to eat till they wash their hands up to the wrist, in obedience to the tradition of the elders; they decline to eat what comes from the market till they have washed it; and they have a number of other traditions to keep about washing cups and jugs and basins [and beds].) read more.
Then the Pharisees and scribes put this question to him, "Why do your disciples not follow the tradition of the elders? Why do they take their food with 'common' hands?"

You drop what God commands and hold to human tradition. Yes, forsooth," he added, "you set aside what God commands, so as to maintain your own tradition.

The Pharisee was astonished to see that he had not washed before the meal,

Now when Pilate saw that instead of him doing any good a riot was rising, he took some water and washed his hands in presence of the crowd, saying, "I am innocent of this good man's blood. It is your affair!"

When the days for their purification in terms of the Mosaic law had elapsed, they brought him up to Jerusalem to present him to the Lord

associate yourself with them, purify yourself with them, pay their expenses so that they may be free to have their heads shaved, and then everybody will understand there is nothing in these stories about you, but that, on the contrary, you are guided by obedience to the Law.

Then Paul associated himself with the men next day; he had himself purified along with them and went into the temple to give notice of the time when the days of purification would be completed ??the time, that is to say, when the sacrifice could be offered for each one of them.

Now the passover of the Jews was near, and many people went up from the country to Jerusalem, to purify themselves before the passover.

who gave himself up for us to redeem us from all iniquity and secure himself a clean people with a zest for good works.