From “A Body of Divinity,” (p. 6).
This is part of the glory we give to God, who counts himself glorified when he is loved. Deut. vi. 5. “Though shalt love the Lord thy God with all thy heart, and with all thy soul.” There is a twofold love: 1. Amor concupicentice, a love of concupiscence, which is self-love; as when we love another, because he does us a good turn. A wicked man may be said to love God, because he has given him a good harvest, or filled his 
cup with wine. This is rather to love God’s blessing than to love God 2. Amor amicitice, a love of delight, as a man takes delight in a friend. This is love God indeed; the heart is set upon God, as a man’s heart is set upon his treasure. This love is exuberant, not a few drops, but a stream. It is superlative; we give God the best of our love, the cream of it. Cant. viii. 2. “I would cause thee to drink of spiced wine of the juice of my pomegranate. If the spouse had a cup more juicy and spiced, Christ must drink of it. It is intense and ardent. True saints are seraphims, burning in holy love to God. The spouse was amore perculsa, fainting fits, “sick of love.” Cant. ii. 5. Thus to love God is to glorify him. He who is the chief of our happiness has the chief of our affections.
-Thomas Watson
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