I am helping a charity and I need to invite my friends to join in. We're not asking for any money or valuables but just their time for some feedback on few questions.
I am struggling at the opening line of the invitation message—what I want to say is that "I need your help in this great work / noble work" but it just doesn't sound that impressive/catchy.
Jihad or movement both describe something too big to describe "answering a few questions."
Please note that it is for non-native English speakers.
Best Answer
I would look at this question: what's the opposite word for 'sin'. About the best you can do is "I performed a good/virtuous/righteous/moral/meritorious act/deed."
Again, there's not a single word that does what you want. Since this is for non-native English speakers, you may as well use the simplest, most direct choice of words. If you're really looking for a single word, you could try jihad or movement, but these have all kinds of other connotations and don't work well for your stated purpose
Endeavor, undertaking, task. . . If these words are too big, then stick with "good/great work". It doesn't need to be "catchy" or "impressive" to be effective. Sometimes a clear, simple, direct message is all you need, especially for people who may not know much English.
If you really need some buzzword or catchphrase to make an impact, consider hiring a PR firm!