"Be ye therefore perfect, even as your Father which is in heaven is perfect." (Matthew 5:48)
Since God is Creator of the universe, all that He does is right, and all He says is truth, by definition. The world He created was perfected; the Word He inscripturated is perfect; every work He accomplishes is perfect; all the ways He follows are perfect, and the will He reveals is perfect.
His perfect world: "And God saw every thing that he had made, and, behold, it was very good" (Genesis 1:31). Of course, because of sin, the creation is now groaning in pain, but it was perfect as it came from God in the beginning. It will again be perfect in the ages to come, when God makes "all things new" (Revelation 21:5).
His perfect Word: "The law of the LORD is perfect, converting the soul" (Psalm 19:7). God has given us His inspired Word, providing perfect guidance for every need, "that the man of God may be perfect" (2 Timothy 3:17).
His perfect works: "He is the Rock, his work is perfect: for all his ways are judgment: a God of truth and without iniquity, just and right is he" (Deuteronomy 32:4). Not only His work in creation but also His works of redemption and reconciliation--all His works throughout history.
His perfect ways: "As for God, his way is perfect: the word of the Lord is tried: he is a buckler to all those that trust in him" (Psalm 18:30). His ways may not be our ways (Isaiah 55:9), but always, they are the best ways.
His perfect will: "And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that . . . perfect, will of God" (Romans 12:2). His will is invariably right.
Thus God is our standard of perfection, and we must never set a lower standard for ourselves. "Be ye therefore perfect, even as your Father which is in heaven is perfect"