Experiential religion is knowing the Triune God personally.  It is described by F.W. Krummacher in his sermons on the life of David in the sermon on David calling Mephibosheth to himself in 2 Samuel 9.  Krummacher writes,

Until that time he [the sinner awakened out of his death-sleep]] knew Him [Jesus the Lord of lords] only as an object of thought from the report of others, but he is now personally and immediately acquainted with Him as the true, living Governor of the world as well as of the saints in Israel, and also as his own Ruler and Judge.  His knowledge, derived from an acquaintance with the Catechism, of the Lord of al lords, remains with him only as a phantom or as a dogma, until he makes an advancement to a truly personal contemplation and experience of Him.

How vital such a progression is!  How it differentiates the notion from the life of faith.  How it discriminates between the precious and the vile, that which passes away and that which endures.  The effect of such “advancement” is clear,

The first impression which an actual meeting with Him as a general rule produces, will, because of the consciousness of an entire estrangement from Him, be one that awakens uneasiness.