Blue color cloth

Number 4:1-28
Kohathites branch of the Levites, all men from thirty to fifty years of age who come to serve in the work in the Tent of Meeting.
All the articles used for ministering in the sanctuary, wrap them in a blue cloth. Bronze altar remove the ashes from it and spread a purple cloth over it.
The Kohathites must not go in to look at the holy things, even for a moment, or they will die.
Aaron and his sons are to go in and take down the shielding curtain and cover the ark of the testimony with it. Cover this with hides of sea cows, spread a cloth of solid blue over that and put the poles in place.
Eleazar son of Aaron, the priest, is to have charge of the oil for the light, the fragrant incense, the regular grain offering and the anointing oil. He is to be in charge of the entire tabernacle and everything in it, including its holy furnishings and articles.
Count all the men of Gershonites by their families and clans, Count all the men from 30 to 50 years old to serve in the work at the Tent of Meeting. They are to carry the curtains of the tabernacle, the Tent of Meeting, its coring and the outer covering of sea cows....
Their duties are to be under the direction of Ithamar son of Aaron, the priest.
Why?
Holy place only Aaraon and his sons may enter and set up all of the articles. The Kohathites so the work of labor to move. It is most closer to the Holy place.
Gershonite do the work outside of the tabernacle, curtains..
The second census of Levites lists those between 30 and 50, eligible to take care of God's tent.
Kohathites are responsible for carrying the sacred objects of the sanctuary after the priests have dismantled and covered them.
The Gershonites are in charge of transporting the curtains and coverings of the Tent and forecourt under Ithamar's supervision.
Only the Priest may enter the to sacred place, how mercy we have we may enter to the present of the Lord through the blood of Jesus Crist. For all of us are unclean.
May be Hebrew think the heaven of the place of God, sky is blue color so blue color be used for spreading the sacred articles.
How?
How precious of a Christian, for the redeem from Jesus Christ we are free from sin, Praise to the Lord