The idea that certain kinds of objects, formulas, or persons can have intrinsic special or even supernatural power is directly antithetical to Christian faith and teaching. And any kind of attribution of the "spiritual" or the supernatural to such things approaches, if not crosses over into, idolatry.
The inherent danger in allowing ourselves to believe in such things is that the devil desires to cloud the mind, in order to obscure Christ from us--and Christ is our one and only hope and salvation. Anything that can distract us, obscure us, to turn our gaze away from Christ to something--anything--else is an intrinsic danger. It is through these sorts of lies and trickery that the devil would have us shipwreck our faith. But, we have the victory that is found in Christ, and we know, just as Luther knew and boldly declared in his hymn,
"And though this world, with devils filled,
Should threaten to undo us,
We will not fear, for God hath willed
His truth to triumph through us:
The Prince of Darkness grim,
We tremble not for him;
His rage we can endure,
For lo! his doom is sure,
One little word shall fell him."
Amen. One little word can leave the devil desolate and beaten, call him "liar" and his entire farce is exposed, his craftiness shown to be the vanity that it is. The emperor has no clothes.
-CryptoLutheran