Stay Strong Indestructible Unbreakable in Chinese / Japanese...

金剛不壞 is originally a Buddhist term for “The diamond indestructible.”

Sometimes, it's written 金剛不壞身, The diamond-indestructible body.

Outside that context, it still means firm and solid, sturdy and indestructible, unshakable, or adamantine (a mythological indestructible material).

Note: If you order this from the Japanese master calligrapher, the last Kanji will look like the one shown to the right.