'Delusion' in the Bible

Do you not know that unrighteous men will not inherit God's Kingdom? Cherish no delusion here. Neither fornicators, nor idolaters, nor adulterers, nor any who are guilty of unnatural crime,

And if Christ has not risen, it follows that what we preach is a delusion, and that your faith also is a delusion.

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].