“For I am Yahweh who brought you up out of the land of Egypt, to be your God. You shall therefore be holy, for I am holy.”
This is a clear reference to the covenant. He has brought them out of Egypt that they might be His holy people, they are therefore to be holy as He is holy, and that involves maintaining their proper sphere and shunning all that might lead to uncleanness, to degradation, to disease, or to death. It was the attitude of heart that was of the most importance. It is this that lies behind all the teaching on cleanness and uncleanness, that His people might be holy as He is holy.
But holiness goes beyond this as we shall see later. It involves positive obedience to the will of God in all things. It involves loving God, and neighbour, and alien (Leviticus 19:2; Leviticus 19:19; Leviticus 19:34). It involves being humble and contrite (Isaiah 57:15). Essentially it involves God-likeness.