God desired his people to be a peculiar people. He wanted them to stick out. He wanted them to be separate from their neighbors. Many of these peculiarities seem pointless, but the "pointless" peculiarities call attention to (and protect) important peculiarities.
The word in and around Canaan would have been that these guys are weird. "They dress funny, they don't eat perfectly good food, and they take a whole year off from work every seven years." But once people started watching them, they should have seen even weirder things:
They treat the poor, women, and foreigners with kindness and respect. There are no murderers, thieves, or adulterers among them. They don't sacrifice their children to their gods. They don't even have shrine prostitutes or idols. In fact, they seem to only have one god. And their god seems to bless everything they do.Of course, things didn't really shake out that way because they weren't very good at following rules.
So God made himself a new peculiar people. He took people from every tribe and made them his own, this time putting his law in their minds and hearts (cf Jer 31:33) so that they can be the holy people he desires (1 Pet 1:15-16).
We don't always follow the rules so well either, but when we do it can be glorious:
"Christians are indistinguishable from other men either by nationality, language or customs. They do not inhabit separate cities of their own, or speak a strange dialect, or follow some outlandish way of life. Their teaching is not based upon reveries inspired by the curiosity of men. Unlike some other people, they champion no purely human doctrine. With regard to dress, food and manner of life in general, they follow the customs of whatever city they happen to be living in, whether it is Greek or foreign.
And yet there is something extraordinary about their lives. They live in their own countries as though they were only passing through. They play their full role as citizens, but labor under all the disabilities of aliens. Any country can be their homeland, but for them their homeland, wherever it may be, is a foreign country. Like others, they marry and have children, but they do not expose them. They share their meals, but not their wives.
They live in the flesh, but they are not governed by the desires of the flesh. They pass their days upon earth, but they are citizens of heaven. Obedient to the laws, they yet live on a level that transcends the law. Christians love all men, but all men persecute them. Condemned because they are not understood, they are put to death, but raised to life again. They live in poverty, but enrich many; they are totally destitute, but possess an abundance of everything. They suffer dishonor, but that is their glory. They are defamed, but vindicated. A blessing is their answer to abuse, deference their response to insult. For the good they do they receive the punishment of malefactors, but even then they rejoice, as though receiving the gift of life. They are attacked by the Jews as aliens, they are persecuted by the Greeks, yet no one can explain the reason for this hatred." — from the Epistle to Diognetus
Or another picture:
"Though we have our treasure-chest, it is not made up of purchase-money, as of a religion that has its price. On the monthly day, if he likes, each puts in a small donation; but only if it be his pleasure, and only if he be able: for there is no compulsion; all is voluntary. These gifts are . . . not spent on feasts, and drinking-bouts, and eating-houses, but to support and bury poor people, to supply the wants of boys and girls destitute of means and parents, and of old persons confined now to the house; such, too, as have suffered shipwreck; and if there happen to be any in the mines or banished to the islands or shut up in the prisons, for nothing but their fidelity to the cause of God's Church, they become the nurslings of their confession. But it is mainly the deeds of a love so noble that lead many to put a brand upon us. See, they say, how they love one another ..." — from the Apology of Tertullian
We are not perfect. We will not be perfect until Christ comes and makes us, finally, like him. But we can strive to imitate him. When we love like he loved us, that kind of peculiarity will stick out. The world cannot miss it. And then they will ask us the reason for the hope that is in us. And the lost will be saved. And Christ will be glorified.