Read: Genesis 15-17, Matthew 5:27-48
Jesus, more than anyone, knows that no one is perfect (except himself, of course), yet here he is, telling us to be perfect. It’s a bit of an impossible task, if you ask me. But perfection, as most of us would view it, is not what Jesus is calling us to.
Just as he who called you is holy, so be holy in all you do; for it is written: “Be holy, because I am holy.”
1 Peter 1:15-16 (NIV)
In the Hebrew and in Greek, “holy” implies connection with God or the divine. Thus, God is holy and people, things, and actions may be holy by association with God.
Harper’s Bible Dictionary
Jesus is not calling us to be something that we can never be, but rather, he is calling us to be close to that which he wants us to be. Perfection this side of Heaven is impossible. Our humanity makes it so. But, J. Newton Davies said that the perfect man was the man who had set his feet on the true path and was still advancing.
In a very small nutshell, the sermon Jesus is preaching in Matthew 5 is all about how, if we are followers of God, we should act like it and the world should know it. Not committing adultery isn’t good enough, you shouldn’t even think about it. You shouldn’t have to swear an oath because your word should be good enough. If someone strikes you on the right cheek, turn and let him hit the other side. Love your neighbours and love your enemies, too. Being holy means being and acting different than those around us.
The perfection is not sinlessness, but a complete control by God’s Spirit.
The International Bible Commentary
The closer we walk with God, the more our actions will reflect it. If you want to be perfect, you have to hang around with someone who is perfect. If you want to be holy, you have to spend time someone who is holy. And the closer you get to that person, the more like them you will become.
The path to perfection is not a solo journey. There is only one path and it can only be travelled side-by-side with the One who is perfect. You may never achieve perfection in this life, but that doesn’t mean you can be still advancing toward it.