Because it is written, Be ye holy; for I am holy.
Leviticus 11:44
For I am the LORD your God: ye shall therefore sanctify yourselves, and ye shall be holy; for I am holy: neither shall ye defile yourselves with any manner of creeping thing that creepeth upon the earth.
Leviticus 19:2
Speak unto all the congregation of the children of Israel, and say unto them, Ye shall be holy: for I the LORD your God am holy.
Leviticus 20:7
Sanctify yourselves therefore, and be ye holy: for I am the LORD your God.
Amos 3:3
Can two walk together, except they be agreed?