We come before the Lord as His people, and we commune with the Lord through the means that He has established. If this is disconcerting, we may reject these means, and flee from Him, as the open infidel does.
But we may also be cowardly infidels, and think that we cannot risk open flight—after all, God the Judge might see us. When this is the case, we often take refuge in the subtleties of our own heart, and we turn the means He gave us to approach Him into a means of shrinking back.
The Word of God says that the Lord has no pleasure in the one who hesitates and shrinks back. The just live by faith, the Word says, and the only alternative to faith in Hebrews 10 is just this shrinking back. Drawing back, hesitating, the erecting of barriers, all of them end in perdition. But those who believe, those who have faith, are ones who believe to the saving of the soul.
If your hand holds the bread of the Lord in faith, it can hold nothing else. If your hand holds the cup of the new testament, you cannot believe and drink anything else alongside that new testament. And to make the attempt is to break covenant. So this is a call to faith, and not to a mental trick. Be warned that all mental tricks are accommodations to the flesh, and are designed to get you removed from the presence of God, into a position of relative safety. But the safety is illusory.
The only refuge from God is in God. If you would flee from Him successfully, you must meet with Him. Not only so, but you must do this by sitting down at Table with His Son. That is why we are here. Come, your place is set.