Levites from among the Israelites in place of the first male offspring

Numbers 3:1-51
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.
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.
The total number of Levites counted at the Lord’s command by Moses and Aaron according to their clans, including every male a month old or more, was 22,000.
The total number of firstborn males a month old or more, listed by name, was 22,273. To redeem the 273 firstborn Israelites who exceed the number of the Levites,  collect five shekels for each one, according to the sanctuary shekel, which weighs twenty gerahs.  Give the money for the redemption of the additional Israelites to Aaron and his sons. 
From the firstborn of the Israelites he collected silver weighing 1,365 shekels. Moses gave the redemption money to Aaron and his sons, as he was commanded by the word of the Lord.
God's claim on the firstborn goes back to the night of the Passover. Now the Levites replace the firstborn of all Israel on special assignment to assist the priests in the service of God. But the census showed that the firstborn of Israel outnumbered the Levites by 273 and to redeem these a payment must be made.
Why?
God redeem Israelite from Egypt so Israelite need devote the firstborn to the Lord.
It is a action to fear the Lord and give honor to the Lord. When we give first achievement to the Lord, God will blesses us much more. For it is the grace of the Lord that we may have many in our life.
How?
Give what belongs to the Lord, then God's grace and blessing is coming to us.