Ephesians 1:4 Even as He chose us in Him before the foundation of the world to be holy and without blemish before Him in love, 1 Samuel 2:2 [There is] none holy as the LORD... 2 Peter 1:4 Through which He has granted to us precious and exceedingly great promises that through these you might become partakers of the divine nature...
God chose us that we should be holy... In the Bible the word “holy” should not be understood according to our natural concept. Many think that holiness is sinlessness.
According to this concept, someone is holy if he does not sin. This thought is absolutely mistaken. Holiness is neither sinlessness nor perfection.
Holy not only means sanctified, separated unto God, but also different, distinct, from everything that is common. Only God is different, distinct, from all things. Hence, He is holy; holiness is His nature.
The way God makes us holy is to impart Himself, the Holy One, into us so that our whole being may be permeated and saturated with His holy nature. For us, God's chosen ones, to be holy is to partake of His divine nature and to have our whole being permeated with God Himself. This is different from mere sinless perfection or sinless purity.
This makes our being holy, like God Himself in His nature and in His character. Therefore, to be holy we need to be one with God because only God is holy.