He is our God. ...If He is our God, we are under obligations to obey Him, to do His will. We belong to Him. Then, if He is our God, He belongs to us, and we have a claim on Him...All He is is ours -- His love, His grace, His goodness, His truth, His mercy.
If God is our God, we should love Him. He is the God to whom we owe everything, from whom we came, to whom we go, who cares for us, watches over us, provides for us, keeps us. He is our Father, with all a father's love.
We ought to love God for Himself, for what He is in His character--merciful, gracious, holy, loving, good. We ought to love Him, too, for what He has done for us. Surely the commandment (Mark 12:29-30) is reasonable.
By often thinking of God, the heart will be enticed into desires after Him. ~W. Gurnall.
Some people want to see God with their eyes as they see a cow, and to love Him as they love their cowfor the milk and cheese and profit it brings them. This is how it is with people who love God for the sake of outward wealth or inward comfort. They do not rightly love God, when they love Him for their own advantage. Indeed, I tell you the truth, any object you have in your mind, however good, will be a barrier between you and the inmost Truth. ~Meister Eckhart (1260?-1327?)
He so governs and shapes all the circumstances of life, that if we use them aright we may draw near to Him here, and prepare to be near Him in the Forever after. He longs for our love,--our love, which is so feeble and faint, and yet so precious in His sight when we give it to Him freely. And why does He so desire it? Ah! I have told you many times before, and yet we cannot too often remember it, that it is because, if we love Him, He can make us supremely happy. All that belongs to us, or occurs to us, in this life, is so ordered that we may find in it the means of putting far from us those obstructions of evil which prevent us from seeing Him as He is, and as He has revealed Himself to us; for if we did but so see Him, how could we fail to love Him with the whole heart and soul? ~Theophilus Parsons
How shall we become lovely? By loving Him who is ever lovely. ~St. Augustine
Your God is love; love Him and in Him all men, as His children in Christ. Your Lord is a fire; do not let your heart be cold, but bum with faith and love. Your Lord is light; do not walk in darkness. Your Lord is a God of mercy and bountifulness; be also a source of mercy and bountifulness to your neighbors. ~Father John
I love my God, but with no love of mine
For I have none to give;
I love Thee, Lord, but all that love is Thine,
For by Thy life I live.
I am as nothing, and rejoice to be
Emptied and lost and swallowed up in Thee.
~Mme. Guyon (1648-1717)
To the Christian, love is the works of love. To say that love is a feeling or anything of the kind is really an un-Christian conception of love. That is the aesthetic definition and therefore fits the erotic and everything of that nature. But to the Christian, love is the works of love. Christ's love was not an inner feeling, a full heart and what-not: it was the work of love which was his life. ~Søren Kierkegaard (1813-1855), Journals
Let all our employment be to know God; the more one knows Him, the more one desires to know Him. And as knowledge is commonly the measure of love, the deeper and more extensive our knowledge shall be, the greater will be our love; and if our love of God were great we should love Him equally in pains and pleasures.
~Brother Lawrence (c.1605-1691), The Practice of the Presence of God.
A Christian should always remember that the value of his good works is not based on their number and excellence, but on the love of God which prompts him to do these things. ~Juan De La Cruz
C. S. Lewis prayed a great deal. I don't think I've ever come across a person who prayer so much- in a train, on a bus, on a walk, or just standing outside. The thing that struck me about him more than anything was that this man really loved God. ~Walter Hooper
Prayer doesn't consist of thinking a great deal, but of loving a great deal. ~Saint Teresa
All love in general hath an assimilating efficacy; it casts the mind into the mould of the thing beloved... Every approach unto God by ardent love and delight is transfiguring. ~John Owen (1616-1683)
Now this is the ground and original of the Spirit of Love in the creature; it is and must be a will to all goodness; and you have not the Spirit of Love in you till you have this will to all goodness at all times and on all occasions. You may indeed do many works of love and delight in them, especially at such times as they are not inconvenient to your state or temper or occurrences in life. But the Spirit of Love is not in you till it is the spirit of your life, till you live freely, willingly, and universally according to it.
~William Law (1686-1761), The Spirit of Love, 1-4
The whole being of any Christian is Faith and Love... Faith brings the man to God, love brings him to men. ~Martin Luther (1483-1546)
Whoever loves much, does much. ~Thomas à Kempis, Of the Imitation of Christ
The world would use us just as it did the martyrs, if we loved God as they did.
~Thomas Wilson (1698-1755)
We must face the recognition that what the early Christians saw in Jesus Christ, and what we must accept if we look at him rather than at our imaginations about him, was not a person characterized by universal benignity, loving God and loving man. His love of God and his love of neighbor are two distinct virtues that have no common quality but only a common source. Love of God is adoration of the only true good; it is gratitude to the bestower of all gifts; it is joy in holiness; it is "consent to Being." But the love of man is pitiful rather than adoring; it is giving and forgiving rather than grateful. It suffers for them in their viciousness and profaneness; it does not consent to accept them as they are, but calls them to repentance. The love of God is nonpossessive Eros; the love of man pure Agape; the love of God is passion; the love of man, compassion. There is duality here, but not of like-minded interest in two great values, God and man. It is rather the duality of the Son of Man and Son of God, who loves God as man should love Him, and loves man as only God can love, with powerful pity for those who are foundering.
~H. Richard Niebuhr (1894-1962), Christ and Culture 
God has made thee to love Him, and not to understand Him. ~Voltaire