We understand God through His attributes, or characteristics. The Bible goes to great lengths to not leave us in the dark as to who our Redeemer is regarding His character, and there are great books written about God and His attributes.
Holiness means God is without sin, and is separate from sin, and is incorrigible. The prophet Habakkuk said in Chapter 1:13 “You are of purer eyes than to behold evil, and cannot look on wickedness.” Proverbs goes even further in Chapter 6: 16-19, instructing us that God hates sin: “These six things the Lord hates, Yes, seven are an abomination to Him: A proud look, A lying tongue, Hands that shed innocent blood, A heart that devises wicked plans, feet that are swift in running to evil, A false witness who speaks lies, And one who sows discord among brethren.”
God not only is without sin, and hates sin, He is against the sinner, as we see in 1 Peter 3:12: “For the eyes of the Lord are on the righteous, And His ears are open to their prayers; But the face of the Lord is against those who do evil.” So, what we learn from these scriptures is that God cannot delight in, accept, approve of, or ignore iniquity. At all. Ever.
Peter sums up our duty as Christians in this manner: 1 Peter 1:15-16: “but as He who called you is holy, you also be holy in all your conduct, 16 because it is written, “Be holy, for I am holy.”