For Aaron's sons you shall make coats and sashes and caps. You shall make them for glory and beauty. And you shall put them on Aaron your brother, and on his sons with him, and shall anoint them and ordain them and consecrate them, that they may serve me as priests.
This entire chapter in Exodus goes into great detail about the attire for the high priest and the priests who would serve under him. There was a huge symbolism to what the high priest wore. Some of the symbols were meant to draw attention to God, others were to draw attention to the people of Israel. This dual symbolism visually defined the role of the priest as mediator between God and Man.
What I notice from these two verses has to do with what God expected. He expected Moses and the nation to set these mean apart through three things: anointing them, ordaining them, and consecrating them. Each has a slightly different meaning. The way they were anointed with oil symbolism God’s calling and power upon them. They received as a special call and designation from God that was being recognized in the ceremonial anointing with oil. They were ordained which really emphasizes the calling of God upon them. This let the nation know that God had a special, unique purpose for the priests and the work of the tabernacle. Not everyone was to do it, but only those specifically called by Him and ordained by the people. And finally they were to be consecrated. The hugely detailed levitical laws would ensure that the priests would be set apart with a different lifestyle. They were uniquely priests to God. They were consecrated to His work and worship alone.
And all these three means of setting apart the priests emphasized their task: to serve God. There would always be a place among the Israelites were God was being worshiped, served, and exalted as Holy as Israel humbled themselves before Him. Sin would be atoned. Grace would be extended. All of this came about because God called a select group, and the nation responded with recognition and provision for that call, so that those set apart to serve God could do so to the joy and delight of God and man.