The Levites are mine, for all the firstborn are mine

Numbers 3:1-39

This is the account of the family of Aaron and Moses at the time the Lord spoke to Moses at Mount Sinai.

The names of the sons of Aaron were Nadab the firstborn and Abihu, Eleazar and Ithamar. Those were the names of Aaron’s sons, the anointed priests, who were ordained to serve as priests. Nadab and Abihu, however, died before the Lord when they made an offering with unauthorized fire before him in the Desert of Sinai. They had no sons, so Eleazar and Ithamar served as priests during the lifetime of their father Aaron.

Appoint Aaron and his sons to serve as priests; anyone else who approaches the sanctuary is to be put to death.

The Lord also said to Moses, “I have taken the Levites from among the Israelites in place of the first male offspring of every Israelite woman. The Levites are mine, for all the firstborn are mine. When I struck down all the firstborn in Egypt, I set apart for myself every firstborn in Israel, whether human or animal. They are to be mine. I am the Lord.”

The Lord said to Moses in the Desert of Sinai, “Count the Levites by their families and clans. Count every male a month old or more.” So Moses counted them, as he was commanded by the word of the Lord.

To Gershon belonged the clans of the Libnites and Shimeites; these were the Gershonite clans. The number of all the males a month old or more who were counted was 7,500.

To Kohath belonged the clans of the Amramites, Izharites, Hebronites and Uzzielites; these were the Kohathite clans.  The number of all the males a month old or more was 8,600.

To Merari belonged the clans of the Mahlites and the Mushites; these were the Merarite clans. The number of all the males a month old or more who were counted was 6,200. 

Moses and Aaron and his sons were to camp to the east of the tabernacle, toward the sunrise, in front of the tent of meeting. They were responsible for the care of the sanctuary on behalf of the Israelites. Anyone else who approached the sanctuary was to be put to death.

Why?
In the old testament, only the family of Aron could be priests to serve the Lord. After Jesus came, everyone accepted Jesus as our Lord and repented our sins, we could be servants of the Lord. For Jesus became our way to build a new relationship between us and the Lord.

The Lord knows the number of everyone who serve the Lord in faith and love

How?

To be a Christan is the love of the Lord comes upon us, so we should love others either.