If you go about undertaking tasks for other people JUST for the thanks they will give you, not for the help you will be doing them, have you committed a sin?
You have done a act of kindness towards the person however if your only doing that kind act for the praise and thanks you will get have you sinned?
The question is a bit complicated, because of the different ways to view “sin”
“Sin” from the Greek “Hamartano”, doesn’t just mean breaking a rule…It means: “error”…“missing the mark”…“Having no part in”.
However - most people DO equate sin with the violation of God’s commands…So
In the case of doing something for the selfish reason of gaining praise, one has not broken any rule…So the answer is no you have not “sinned” in this sense.
But the thing is that, while one has not “sinned” (violated a law), neither has one hit the mark.
Jesus said that if someone does something for the notice and praise of others, they have already received their reward…Better to do things in secret and thereby build up treasure in heaven.
Of course if one does something for another - not for pay or praise, but rather out of love of neighbor and of God - and receives thanks from the other this does not negate the treasure in heaven. It has to do with intent.
So - if you ONLY do things for those who will praise you, then you have “Missed the mark”; you gain no treasure in heaven and so you “have no part in” heaven based on these works…
In the final analysis, the whole matter resolves itself down to Love…
Do - or don’t do - out of Love.
Expect no thanks, but graciously accept any offered.
Keep the focus on God, on Love and on going Good for the sake of the kingdom.
THAT is hitting the mark. That is having a share in. That is keeping the law - of Love…
Peace
James