'Subtly' in the Bible

Go, I pray you, make yet more sure, and know and see his place where his haunt is, and who hath seen him there; for it is told me that he dealeth very subtly.

He turned their heart to hate his people, To deal subtly with his servants.

while our more presentable parts do not require it. But God has combined the [whole] body, giving greater honor to that part which lacks it,

But [in those days] false prophets arose among the people, just as there will be false teachers among you, who will subtly introduce destructive heresies, even denying the Master who bought them, bringing swift destruction on themselves.