In one very real sense, Christians are clearly far from perfect. Even the most mature Christian believer sins in thought, word, deed, and motive. In fact, increasing awareness of sin is a mark of spiritual maturing; the more we grow in faith, the more aware we will become of the presence of sin in our lives (1 Timothy 1:15). John Piper writes
The mark of the saint is not sinlessness but sin-consciousness! The evidence of indwelling truth is the exposure of error. The dawning of God's light in the heart is the revelation of remaining darkness. In this life, we never get beyond the awareness of remaining sin. Therefore, one of the great signs of maturity in Christ is a deep and abiding brokenness for sin...The mark of a new creature in Christ is not a rosy self-concept. It is brokenness for remaining sin mingled with a joyful confidence in the superabounding grace of God in Christ.
Christians still sin, we still falter and fumble and fail, we still fall woefully short of what God would have us do and be, and we still need God's grace and forgiveness on a continual basis. In Philippians 3:12, the Apostle Paul writes, "Not that I have attained, or am already perfected, but I press on, that I may lay hold of that for which Christ Jesus has also laid hold of me." Paul is looking ahead to the future prize of his salvation in all its fullness. He is already saved by grace through faith, and he has tasted some of the blessings attached to being saved, but he has not yet experienced the consummation or culmination of his faith in its fullest sense. In this life, he still experiences sin, he still struggles with temptation, and self-gratification, and evil desires (Romans 7); he is not yet made perfect in his being.
On the other hand, the Bible also teaches that God counts Christ's perfection as our own when we are saved and united to Christ by faith (1 Corinthians 1:30; 2 Corinthians 5:21; Philippians 3:9). So another equally true, co-existing reality is that in Christ, the Christian has
fulfilled all of God's perfect and perfectly righteous requirements (Matthew 5:48; James 2:10). Christ is our righteousness which means that His perfect sinless obedience is imputed to us; it is counted as our own.
So, are Christians perfect? Is it possible to attain the perfection commanded in Matthew 5:48? Yes and no. Yes, in Christ only, as it applies to our relationship with God and our eternal identity and security in Him who satisfies God's perfect standards of holiness. And no, not in our flesh, as we remain attached to our sin nature in our pre-glorified state.
One last thought. Being perfect in
Christ means something that is very and essentially different to me and about me than if I were to claim to be perfect through
Christ. If I am an astronaut and hitch a ride in a rocket into space, no one assumes that I arrived there on my own power. It's clear that the only way I ever make it into space is because the rocket, with its thrusters and propellants and stages, does all the work of overcoming inertia and earth's gravity to raise itself (and me with it) up through the atmosphere and into space. Likewise, if I am perfect in Christ, it means that He is the perfect one, and I am simply a passenger, enjoying the benefits of His perfection. However, if I say I am perfect through Christ, I am implying that Christ has enabled me, myself, to be perfect. While it's true to say that Christians in this life are perfect in Christ, it's only true because Christ, and not themselves, is perfect. So, by the same token, it would not be true for believers to claim to be perfect through Christ. Or I should say, it wouldn't be true of us yet. Only glorified Christians whom God calls home into His presence, fully imparting to them the inward beauty of holy perfection, can truthfully say that through Christ they are finally, themselves, perfect.
God bless you as you seek God in His Word!