"And you shall love the Lord your God..."
Fearing G-d, without which man cannot merit holiness or purity, is itself a prerequisite to loving Him, the second stage of man's spiritual growth as he proceeds to accept upon himself the yoke of Heaven. Loving G-d is a more exalted stage, as our sages said (Sotah 31a), "One motivated by love for G-d is greater than one motivated by fear."A love song to HKB"H...
...Fear of G-d distances man from evil, whereas love of G-d ensures that he will do good, out of desire and craving for G-d and His commandments. The more a person ponders G-d's wonders and examines the truth of His attributes and moral code, the more he will understand how much wisdom and truth are contained in them and the more there will grow within him a love for the Master, Who is all goodness, kindness and mercy. Ultimately, that love will be so fierce and profound that it will capture his spirit and soul. It will be a love of true devotion, as it says, "To love the L-rd your G-d, to hearken to His voice and to cling to Him" (Deut. 30:20).
[Or Hara'ayon, Chapter Four: "Ahavat Hashem (The Love of G-d,)" pp. 71-72]