“But to us there is but one God, the Father, of whom are all things, and we in Him; and one Lord Jesus Christ, by whom are all things, and we by Him.” (1 Corinthians 8:6)
“For the invisible things of Him (God) from the creation of the world are clearly seen, being understood by the things that are made, even His eternal power and Godhead; so that they (deniers) are without excuse.” - Romans 1:20
IF these deniers can be convinced there is a real source of evil which manipulates the hearts of men then we have a leg by which to show them something profound about GOD. Here's why:
God created the source of evil before it became evil. The nature of angelic existence is eternal, never going out of existence. As such, the author of lies a murderer from the start would be manipulating God if THE GOD was constantly reacting to the evil the author evil manipulates men into doing. Example of Hitler: if the author of evil could manipulate Hitler into doing unspeakable evil things, which he did, the author of evil I mean, then God would be constantly reacting rather than being The Uncaused Cause. Inroad of being manipulated constantly, The God has a plan to use the evil to eventually achieve His ultimate good purposes. The God, knowing the end from the beginning, is not manipulated by the one who chose to be evil. The God is defeating that one by a longer range plan than the evil one can comprehend, so the evil one is constantly trying to thwart what that evil one sees as the plan, not knowing the ultimate plan.
The seed of the woman (a virgin born chosen One of God) will crush the head of the seed of the evil one. So satan tries to destroy the DNA of humanity, to prevent a seed of the woman Savior from being possible for the human race turned not human. The Jews are the chosen people through whom God will bring the seed of the woman, so satan tries to destroy Israel. In the end times Tribulation, the Jews are foretold to be populating the millennial kingdom of God, so satan tries to destroy all of Israel, all the descendant of Jacob. And so it goes, satan being the one actually reacting, God unfolding HIS plan.
Put in a short form, God cannot be tempted nor does He tempt humanity; satan is seeking to tempt God into reacting and thus being under satan's influence, by manipulating men to do such evil deeds.