be oneself为习语，《牛津词典》的解释为：

to be in a normal state of body and mind, not influenced by other people 做自己。

One needs space to be oneself.

through thick and thin也是习语，意为：不顾艰难险阻； 在任何情况下

If we can allow our children to be themselves without prejudice, they’ll build friendships with people, regardless of race or religion, who will be by their side through thick and thin. 

如果我们允许我们的孩子不带偏见地做自己，他们就会与不同种族或信仰的人结成友谊，这些人会和他在一起克服艰难困苦。