You therefore must be perfect, as your heavenly Father is perfect.
Matthew 5:48 ESV
The command is to be perfect. It comes after a “therefore.” Jesus just got done telling the people that they have to love their enemies and that they can’t just be like everyone else. They are called to more. In fact, they are called to be perfect.
That word “perfect’ means complete, mature, full grown. We get that in Christ. Colossians 2:10a You have been made complete in Christ. He is the perfection that we could never attain on our own. We shouldn’t think it’s impossible because what’s impossible with man is possible with God (Luke 18:27). And we’re to “no longer live” but by faith Christ is to live in us (Gal. 2:20).
He can live the impossible life through us. You might be tempted to think we can be perfect because Christ’s blood washes away our sins, but we can’t love our enemies through forgiveness alone. It’s an action we have to take, and we can live it out through faith in Christ.