"No man needs a window in his breast for God to look in at; every man before God is all window." (John Trapp's Commentary) There is a message that the Lord JESUS wanted all the churches to know in the Apostle John's day. It is the same message for the churches of today. It is JESUS' name or title as being - "I am He Which searcheth the reins and hearts." He "searcheth all hearts." Therefore, you cannot deceive Him with a profession of religion or an insincere obedience.