Presumptuous
Besides the sin of rebellion there is also that of presumption, which is, that we do what we are not ordered to do.
Rebellion is failing to do what God Has Charged, whereas presumption is doing what God has not commanded at all.
To be active outside of the Lord’s Will is to be presumptuous.
It is reckoned as sin before the Lord if we work for Him without His Command and instead work according to our own idea, even though we may view what we do to be most excellent.