He has a window into your heart!
(George Everard, "Little Foxes, and How to Catch Them!" 1878)
"You hypocrites! Isaiah was right when he prophesied about you: These people honor Me with their lips, but their hearts are far from Me!" Matthew 15:7-8
Many professing Christians go to church from Sunday to Sunday, but in God's sight their worship is altogether in vain, as they offer their listless, heartless prayers. The lips speak — but the heart is dumb. The knee is bent — but the soul is unhumbled. Their thoughts are to the ends of the earth. Whether it is the prayers or the hymns — it matters not; for business and a multitude of worldly matters engage the mind, and there is no room for true worship.
Those who go regularly from habit to the House of God, are often living altogether unmindful of the truths they hear, or of the petitions they offer. Such is mere lip service, and profits nothing — but is rather abomination in the sight of God. How many sit before God as His people — and yet not one solitary petition is offered in earnest during the whole service. All kinds of subjects fill the mind and occupy the attention. Money, dress, business, a coming entertainment, yes even envious and malicious thoughts — are permitted to reign within the heart — and those who are apparently devout worshipers are content to have it so.
If this is so with any reader, remember the grievous sin you commit. God is not mocked. He has a window into your heart, and sees the innumerable multitude of vain thoughts which occupy the temple where He would dwell. You cannot deceive Him with such formal and hypocritical worship.