This is the belief to a certain extent. Some Muslims believe that if they say something like "I have twin girls Ma sha Allah', then their kids will be protected forever. This is not the case. Many Muslims rely on the word Ma sha Allah to protect them, rather than God which is obviously wrong. We must remember that God has control over everything and something like the phrase Ma sha Allah does have an impact therefore it is favoured to say it. There are also "ayat's" that Muslims read for protection, but again we must rememebr that protection comes from God, not from the words we use.

Hope this helps.

God knows best