'Delusion' in the Bible

and if Christ has not been raised, your faith is worthless and powerless [mere delusion]; you are still in your sins [and under the control and penalty of sin].

that, regarding your previous way of life, you put off your old self [completely discard your former nature], which is being corrupted through deceitful desires,

For our appeal does not come from delusion or impure motives, nor [is it motivated] by deceit [our message is complete, accurate, and based on the truth—it does not change].

Because of this God will send upon them a misleading influence, [an activity of error and deception] so they will believe the lie,