“What is the greatest commandment of the New Testament?” This is the question with which Archimandrite Zacharias ended his recent lecture at St Vladimir’s Theological Seminary. I’ve learned that when spiritual fathers ask what seems like an easy question, the answer is rarely the popular or presumed one.

So after the audience shouted out the standard answers such as, “To Love God,” “To love one another,” and “To be holy as your heavenly Father is holy,” Father Zacharias told the audience to open their Bibles and read Luke 17:10.

Luke 17:10 is the punchline to Jesus’ parable on faithfulness as an expression of true faith. The parable is his response to the disciples’ request to “Give us greater faith!”

He replied, “If you have faith as small as a mustard seed, you can say to this mulberry tree, ‘Be uprooted and planted in the sea,’ and it will obey you. Suppose one of you has a servant plowing or looking after the sheep. Will he say to the servant when he comes in from the field, ‘Come along now and sit down to eat’? Won’t he rather say, ‘Prepare my supper, get yourself ready and wait on me while I eat and drink; after that you may eat and drink’? Will he thank the servant because he did what he was told to do? Luke 17:6-9

So are you ready for the greatest commandment of the New Testament?

“So you also, when you have done everything you were told to do, should say, ‘We are unworthy servants; we have only done our duty.’” Luke 17:10

In other words, all of the other New Testament commandments are expected of Christ’s apprentices. But the greatest commandment, the one that is probably the most essential, is a constant attitude of humility as we endeavor to embody all of the commands.

This ties directly to the eldest son in the Story of the Prodigal Son. Remember his complaint to his father?

“Look! All these years I’ve been slaving for you and never disobeyed your orders. Yet you never gave me even a young goat so I could celebrate with my friends. But when this son of yours who has squandered your property with prostitutes comes home, you kill the fattened calf for him!” Luke 15:29-30

On the surface, the eldest son has been working diligently and faithfully for his father. On the outside, he’s the perfect picture of “the good son.” But beneath the external loyalty is a dangerous undercurrent of pride and entitlement. And it corrupts him and causes him to miss perhaps the most important event in his family’s life — his brother has returned from the dead!

Yes, we have been adopted into God’s family and have been embraced as his sons and daughters. But we must not be deceived by a false sense of entitlement, like the stereotypical spoiled brats of royalty. As God’s children, we are called to become truly and fully human as embodied by Jesus. God’s commandments are not arbitrary rules and restrictions, but road signs that lead us to a truly human life. Being God’s children means following Jesus out of our subhuman existence and into the truly human life God intended and that Jesus embodied. It’s not an optional life, but one that is expected of all of God’s children.

To return to Jesus’ parable in Luke 17, the disciples requested a greater quantity of faith. Jesus redirected them to a greater quality of faith. And that quality is humble faithfulness, letting Jesus lead and train us into an obedient and truly human life. This is the mustard seed that can move mountains.

And like servants and apprentices of old, our constant attitude must be, “We are unworthy servants; we have only done our duty.” This is what it means to be God’s sons and daughters.