You therefore must be perfect, as your Father in heaven is perfect.
Every time I read this verse I wonder to myself, “Does the Lord Jesus really know who He is talking to? All of us humans are so flawed, even the very best of us. And it seems like those who make the greatest effort to be 'perfect' make the biggest mess out of themselves.
J.N. Darby asks in his hymn: “And is it so, I shall be like Thy Son?” It's a great hope! But this is vison not of a present earthly reality, but a future heavenly reality.
Our total incapability to be perfect drives us to the One who actually was perfect.
Anything less than perfection in ourselves is absolutely not good enough for us to be satisfied with who we are. As we examine and follow the example of Jesus while He was here on this earth, we actually do move closer towards what He is telling us we must be.
Forgetting what is behind, I press on towards the goal for the prize of the upward call of God in Christ Jesus. Phil: 3:13