God does use sinful men. As Brakel puts it, God uses a crooked stick...
But that does not make man's action any less sinful.

Just like Abraham sinned by lying to Pharao and Abimelech...
Just like Isaac lied by lying to Abimelech...
Just like Jacob deceived his father..
Just like the brothers of Joseph sinned selling Joseph into slavery...
Just like David pretended he was witless in Gaza...
Just like Abraham sinned with Hagar
Just like Jacob sinned having 2 wives
Just like David sinned having multiple wives

God was often long suffering, not punishing the sins of all these holy people. And God used all these sinful actions of sinning saints, for our edification.

All things MUST work together for good, those that love him, and are called according to His purpose. Even the sinful actions of sinful saints. Even the sinful actions of the reprobate, for that matter.

But to transgress God's law is still sin.

__________________
Bert Mulder
Elder of the First Protestant Reformed Church of Edmonton
Edmonton Alberta Canada