What a wonderful way to correct someone. Not the, “OMG, you’re doing it wrong” or “COME ON, you didn’t know that?”.
There are etiquettes to everything especially when it comes to religion. So, when correcting someone don’t make them feel stupid or point them out in front of others. Your correction if done in the wrong way can even put someone off of doing something forever. This is especially horrible when it’s a good deed that you’re putting someone off of.