What is God's purpose for setting believers apart?

God sets believers apart so they are holy and without blame before Him, and so they are intrinsically in His program, to be used as He sees fit, because they belong to Him. This setting apart is for God's purposes, just as holy utensils were reserved only for Him.

The context illustrates this with the priest's utensils: they were holy and set apart only for God's purposes, so they could not be taken home for personal use. In the same way, believers have been set aside for God and are intrinsically in His program, to be used as He sees fit, because they are His. This means being holy, or set apart, and without blame before Him. Though believers still have the old sin nature and still sin, they are sinners saved by grace and are called blameless before Him.

What does it mean that believers are set apart for God's use?

Believers are holy, set apart exclusively for God's purposes, just as priestly utensils were not for common use. They are set aside and intrinsically in His program to be used as He sees fit because they are His, holy and without blame before Him even while still having the old sin nature.