What are walls of salvation and gates of praise?

Violence shall no more be heard in thy land,
wasting nor destruction within thy borders;
but thou shalt call thy walls Salvation,
and thy gates Praise.
(Isaiah 60:18)

Here Isaiah compares salvation to a defensive wall that keeps out everything evil – sin, violence, waste, destruction, and so on. Why is salvation like a wall? It’s because when we repent and are saved from our sins and forgiven, Christ also gives us a new heart and mind that abhors sin. It’s way easier to resist something if you hate it. Hating sin is a better defense against it than any physical barrier ever constructed. (However, we have to be careful that we don’t go too far and hate the sinners as well. That is how Satan uses churches to perpetrate his greatest atrocities, by getting them to hate and persecute the person who sins.)

If we have a salvation-born hatred towards sin that defends us from it, how do we know when to let something in to our lives? The answer is in the next line.

[T]hou shalt call. . . thy gates Praise - Why does Isaiah say we will call our gates praise? We can figure this out if we think about what gates are meant to do. Two of the three functions of a city gate are to let things into a city and keep things out. How does a city know to let something in? When someone good who already knows about it praises it as a good thing. The same thing happens with us individually. When we are trying to decide whether to let something into our lives, we check to see if someone we trust praises it. (As the thirteenth article of faith says, we seek after things that are praiseworthy.) If righteous people praise it, we are willing to look into it, and if they don’t, we avoid it.

In that day shall this song be sung in the land of Judah;
We have a strong city;
salvation will God appoint for walls and bulwarks.
Open ye the gates,
that the righteous nation which keepeth the truth may enter in.
Thou wilt keep him in perfect peace,
whose mind is stayed on thee:
because he trusteth in thee.
Trust ye in the LORD for ever:
for in the LORD JEHOVAH is everlasting strength.
(Isaiah 26:1-4)

Here the idea is repeated that salvation and the attendant change of heart is our defense against sin. And it starts to mention gates again, just like the other scripture did, so we can instantly associate praise with them. And then Isaiah adds something more.

Open ye the gates, that the righteous nation which keepeth the truth may enter in – We are advised to welcome nations and peoples that keep to true principles. We can welcome Muslims for their refreshing standards of sexual purity and modesty. (After browsing some Muslim women clothing websites to check out their fashions, I decided that their evening dresses are the coolest ever—exotic, attractive, and well-covered all at once!) We can welcome Indians and Asians for their commitment to family and education. We can welcome Hispanic warmth and friendliness. There is something good about each culture.

We tend to become suspicious of other cultures when they don’t do things like we do and emphasis the same values. It startles us when we find we can’t take it for granted that that someone knows something we’ve known a long time. However, it is clear to me that just as one person is different from one another, cultures are too. Just like people have different ways of doing things, cultures do too. Just like every person is needed, so is every culture. But just like no person is perfect unless they are like Christ, no culture is perfect, unless it is like Zion. As different cultures have different strengths that are part of the gospel, they also have different weaknesses and need other cultures around as examples to help overcome those weaknesses. When a person embraces the gospel of Christ, it purifies and perfects them toward the ideal—Christ. When whole cultures embrace the gospel of Christ, it purifies them and perfects them toward the ideal society—Zion.

This isn’t the only thing that this line could be referring to. It could also be referring to the return of the Lost Ten Tribes of Israel. Isaiah could be telling us to accept them and welcome them for their righteousness, instead of being suspicious, as many nations are when there is a sudden influx of unfamiliar people.