Numbers 19:12

And do ye abide without the camp seven days: whosoever hath killed any person, and whosoever hath touched any slain, purify both yourselves and your captives on the third day, and on the seventh day.

And he said unto the people, Be ready against the third day: come not at your wives.

Then will I sprinkle clean water upon you, and ye shall be clean: from all your filthiness, and from all your idols, will I cleanse you.

And put no difference between us and them, purifying their hearts by faith.

And I said unto him, Sir, thou knowest. And he said to me, These are they which came out of great tribulation, and have washed their robes, and made them white in the blood of the Lamb.

Purge me with hyssop, and I shall be clean: wash me, and I shall be whiter than snow.

After two days will he revive us: in the third day he will raise us up, and we shall live in his sight.

But the remainder of the flesh of the sacrifice on the third day shall be burnt with fire.

And be ready against the third day: for the third day the LORD will come down in the sight of all the people upon mount Sinai.