If Jesus were to begin a sentence with the phrase, "If you want to be perfect..." - there are several guesses I'd have as to the words He would use to finish.
One of them might be "...then live a perfectly moral life." Popular Christianity seems to focus on the external behaviors of people more than anything else, which makes some sense; because it can be proof that the inner life is aligned with God. But that's not what he says.
Another might be "...then always demonstrate peace and joy in all circumstances." Since heaven is a matter of peace and joy (Rm 14:17), and we are supposed to pray for it to be here on earth as it is in heaven (Mt 6:10), it stands to reason that he might say this, too. Alas, no.
One more option comes to mind: "...then be humble in heart." This would be my top guess, because humility is what Christ said was in His heart (Mt 11:29) and God gives grace to the humble (1 Pt 5:5) and God's grace is what makes us perfect. But He didn't choose these words.
What He said, surprisingly, after starting such a bold sentence was this: "If you want to be perfect, go, sell your possessions and give to the poor, and you will have treasure in heaven. Then come, follow me." (Mt 19:21)
Why? I guess partly, it had to do with who Jesus was talking to when He said it. He was talking to a rich man, who said he wanted to do whatever God required, but had his fists latched too tightly to his wealth to do it.
But partly, I think a person's capacity to give up what they have ("sell your possessions") and then give it freely as a gift to the needy puts us in alignment with the very heart of Christ. Who, more than He, has given up what He possessed (life in heaven) in order to give it freely to the needy (you and me)?
There are a lot of ways for you to give of what you possess to the poor and needy, but today we are pooling some of our money together to fund our church's efforts to take care of some of the poor and needy that are among us with our church family and around us in this city that need this expression of the love of Christ.
When you give to the poor, you are showing some of those other things that I thought Jesus might say: humility, that your peace and joy come from God not your material possessions, and external behaviors that show your inner life is aligned with God.
Thank you, church, for what you will give today.