He did it from gratitude.
You are a man of gratitude.
I cannot express my sense of gratitude in words.
No words can describe my gratitude for your kindness.
I have a debt of gratitude.
I have no words to express my gratitude to you.
He showed no gratitude to you.
He expressed his gratitude for my help.
I want to show you my gratitude.
We noticed her gratitude for that.
You’re very kind to express your gratitude.
His gratitude is quite apparent.
I expressed my gratitude to my friend for his help.
I did it from gratitude and not from fear.