Debarred from public worship, David was heartsick. Ease he did not seek, honour he did not covet, but the enjoyment of communion with God was an urge… - Charles Haddon Spurgeon

"If thou dost continually draw thine impulse, thy life, the whole of thy being from the Holy Spirit, without whom thou canst do nothing; and if thou dost live in close communion with Christ, there will be no fear of thy having a dry heart. He who lives without prayer — he who lives with little prayer — he who seldom reads the Word — he who seldom looks up to heaven for a fresh influence from on high — he will be the man whose heart will become dry and barren; but he who calls in secret on his God — who spends much time in holy retirement — who delights to meditate on the words of the Most High — whose soul is given up to Christ — who delights in his fullness, rejoices in his all-sufficiency, prays for his second coming, and delights in the thought of his glorious advent — such a man, I say, must have an overflowing heart; and as his heart is, such will his life be. It will be a full life; it will be a life that will speak from the sepulcher, and wake the echoes of the future. "Keep thine heart with all diligence," and entreat the Holy Spirit to keep it full; for, otherwise, the issues of thy life will be feeble, shallow, and superficial; and thou mayest as well not have lived at all."

The evil heart which still remaineth in the Christian, doth always, when it is not attacking or obstructing, still reign and dwell within him. My heart is just as bad when no evil emanates from it, as when it is all over vileness in its external developments. A volcano is ever a volcano; even when it sleeps, trust it not. A lion is a lion, even though he play like a kid; and a serpent, is a serpent, even though you may stroke it while for a season it slumbers; there is still a venom in its sting when its azure scales invite the eye. My heart, even though for an hour, it may not have had an evil thought, is still evil. If it were possible that I could live for days without a single temptation from my own heart to sin, it would be still just as evil as it was before; and it is always either displaying its vileness, or else preparing for another display. It is either loading its cannon to shoot against us, or else it is positively at warfare with us. You may rest assured that the heart is never other than it originally was; the evil nature is still evil; and when there is no blaze, it is heaping up the wood, wherewith it is to blaze another day. It is gathering up from my joys, from my devotions, from my holiness, and from all I do, some materials to attack me at some future period. The evil nature is only evil, and that continually, without the slightest mitigation or element of good. The new nature must always wrestle and fight with it; and when the two natures are not wrestling and fighting, there is no truce between them. When they are not in conflict, still they are foes. We must not trust our heart at any time; even when it speaks most fair, we must call it liar; and when it pretends to the most good, still we must remember its nature, for it is evil, and that continually.

He cannot be a glorious God unless His people ultimately are a glorified people.