His elbow is at the top of the photo, wrist to the bottom. The JMS runs on the inside of the arm. The phrase runs in a band around his arm.
**Edited to add: The language is Maori. Maori are the indigenous people of New Zealand. To be completely correct, they're Polynesian and around 1000AD they took canoes (!!!) from Polynesia to New Zealand. Must've been some big-butt canoes! Maori look similar to indigenous Hawaiians.
**Edited again to add: The meaning is the title line "Be Strong. Be Courageous." This is exactly how it is written in the Maori translation of the Bible in the first portion of Joshua 1:9 which says, "Have I not commanded you, be strong and courageous."