You want me to tell you why God is to be loved and how much. I answer, the reason for loving God is God Himself; and the measure of love due to Him is immeasurable love.
He gave Himself for us unworthy wretches? And being God, what better gift could He offer than Himself? Hence, if one seeks for God's claim upon our love here is the chiefest: Because He first loved us (I John 4.19).
But it is hard, nay rather, impossible, for a man by his own strength or in the power of free-will to render all things to God from whom they came, without rather turning them aside, each to his own account, even as it is written, For all seek their own' (Phil. 2.21); and again, The imagination of man's heart is evil from his youth' (Gen. 8.21).
His Body sown in the grave has blossomed in the Resurrection (I Cor. 15.42); and in like manner our valleys and fields which were barren or frozen, as if dead, glow with reviving life and warmth.
So it behooves us, if we would have Christ for a frequent guest, to fill our hearts with faithful meditations on the mercy He showed in dying for us, and on His mighty power in rising again from the dead.
Creation was not so vast a work as redemption; for it is written of man and of all things that were made, He spoke the word, and they were made' (Ps. 148.5). But to redeem that creation which sprang into being at His word, how much He spoke, what wonders He wrought, what hardships He endured, what shames He suffered! Therefore what reward shall I give unto the Lord for all the benefits which He hath done unto me? In the first creation He gave me myself; but in His new creation He gave me Himself, and by that gift restored to me the self that I had lost.
Love is an affection of the soul, not a contract: it cannot rise from a mere agreement, nor is it so to be gained. It is spontaneous in its origin and impulse; and true love is its own satisfaction. It has its reward; but that reward is the object beloved. For whatever you seem to love, if it is on account of something else, what you do really love is that something else, not the apparent object of desire.
Rest is in Him alone. Man knows no peace in the world; but he has no disturbance when he is with God.
I have said already that the motive for loving God is God Himself. And I spoke truly, for He is as well the efficient cause as the final object of our love. He gives the occasion for love, He creates the affection, He brings the desire to good effect.
He has no gift for them better than Himself. He gives Himself as prize and reward: He is the refreshment of holy soul, the ransom of those in captivity.
But here is a paradox, that no one can seek the Lord who has not already found Him. It is Thy will, O God, to be found that Thou may be sought, to be sought that Thou may the more truly be found.
So then in the beginning man loves God, not for God's sake, but for his own.
No longer do we love God because of our necessity, but because we have tasted and seen how gracious the Lord is.
Whosoever praises God for His essential goodness, and not merely because of the benefits He has bestowed, does really love God for God's sake, and not selfishly.
In this life, I think, we cannot fully and perfectly obey that precept, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy strength, and with all thy mind' (Luke 10.27).
And to this degree no human effort can attain: it is in God's power to give it to whom He wills.
The fourth degree of love is attained for ever when we love God only and supremely, when we do not even love ourselves except for God's sake.
Neither fear nor self-interest can convert the soul. They may change the appearance, perhaps even the conduct, but never the object of supreme desire.
Sometimes a slave may do God's work; but because he does not toil voluntarily, he remains in bondage.
Charity, the law of the Lord, joins the Three Persons into the unity of the Godhead and unites the holy Trinity in the bond of peace.
Love is the eternal law whereby the universe was created and is ruled.
The eternal law of righteousness ordains that he who will not submit to God's sweet rule shall suffer the bitter tyranny of self: but he who wears the easy yoke and light burden of love (Matt. 11.30) will escape the intolerable weight of his own self-will. Then freed from the weight of my own will, I can breathe easily under the light burden of love.
In like manner, by God's grace, it will come about that man will love his body and all things pertaining to his body, for the sake of his soul. He will love his soul for God's sake; and he will love God for Himself alone.
Everyone really should read this classic work. The complete text can be read here.