is correct; is right
I know what is right.
Siempre es el momento apropiado para hacer lo que es correcto.
It's always the right time to do what is right.
Everything he says is correct.
Creo que lo que estás haciendo es correcto.
I think what you're doing is right.
Siempre debes hacer lo que es correcto.
You should always do what is right.