Kia kaha
Kia kaha is a Māori phrase used by the people of New Zealand meaning stay strong, used as an affirmation. The phrase has significant meaning for Māori: popularised through its usage by the 28th Māori Battalion during World War II, it is found in titles of books and songs, as well as a motto.
Linguistically, kia kaha consists of the desiderative verbal particle kia, used here as 'an encouragement to achieve the state named', that is, to achieve kaha or strength. Kaha derives from Proto-Polynesian *kafa, meaning "strong" or "great"; *kafa is also the Proto-Polynesian term for sennit rope, a strong rope made from coconut fibres and used for lashing canoes, weapons, and buildings together.
Usage
The phrase is used in several different contexts. It is a term of comfort or solace (an equivalent of be strong - my thoughts are with you), or (less often) it can serve a similar function to 'kia ora' - an interjection during a speech to indicate support or approval (similar to hear! hear!). It is sometimes seen used as a valediction at the bottom of messages.