The more sincere anyone is, the more he makes conscience of his thoughts, and is more observant of them and troubled about them. “Let the unrighteous man forsake his thoughts” (Isaiah 55:7). When a man’s thoughts trouble him, then he begins to be serious, and to have a conscience indeed. So David “I hate vain thoughts: but thy law do I love” (Psalm 119:113).
We think thoughts are free, and subject to no tribunal. If there is any error in them, we think it is a very venial one; they betray us to no shame in the world, and therefore we let them go without dislike or remorse. But a child of God cannot pass over the matter so; he knows that thoughts are the immediate births of the soul, and do much reveal the temper of it. The actions begin there, and if vain thoughts are permitted to lodge there, he will soon fall into further mischief. And therefore he considers what he thinks, as well as what he speaks and does at all times, especially in worship, where the workings of the inward man are of chief regard, and the acts of the outward only required as a help to our “serving God in the spirit” (Philippians 3:3).
Men that have made bold with God in duty, and it succeeds well with them, their awe of God is lessened, and the lively sense of his glory and majesty abated, until it is quite lost. By degrees they outgrow all feelings and tenderness of conscience. Every time you come to God slightly, you lose ground by coming, until at length you look upon worship as a mere custom, or something done for fashion’s sake.
It is an affront to God, and a kind of mockery. We wrong his omniscience, as if he saw not the heart, and could not tell man his thoughts. It is God’s essential glory in worship to be acknowledged as an all-seeing spirit, and accordingly to be “worshipped in spirit and in truth” (John 4:24). Thoughts are as audible to him as words; therefore when you prattle words, and do not make conscience of thoughts, you do not worship him as a spirit. We wrong his majesty when we speak to him in prayer, but do not give heed to what we say.
Surely we are not to prattle, like jays or parrots, words without affection and feeling, or to “chatter like cranes” (Isaiah 38:14), or be like Ephraim, whom the prophet calls “a silly dove without an heart” (Hosea 7:11). You would all judge it to be an affront to the majesty of God if a man should send his clothes stuffed with straw, or a puppet dressed up instead of himself, into the assemblies of God’s people, and think this should supply his personal presence —the absence of the spirit is the absence of the more noble part. We pretend to speak to God, and do not hear ourselves, nor can give any account of what we pray for.