This short question is among the most profound questions ever asked. And no human would ever be able to answer it sufficiently. One thing is certain, however. God does not love us because we are lovable or because we deserve His love. If anything, the opposite is true. The state of mankind since the fall is one of rebellion and disobedience. Jeremiah 17:9 describes man’s inner condition: “The heart is deceitful and desperately wicked. Who can know it?” Our innermost beings are so corrupted by sin that even we don’t realize the extent to which sin has tainted us. In our natural state, we do not seek God; we do not love God; we do not desire God. Romans 3:10-12 clearly presents the state of the natural, unregenerate person: “There is none righteous, no, not one; There is none who understands; There is none who seeks after God. They have all turned aside; They have together become unprofitable; There is none who does good, no, not one.” How then is it possible for a holy, righteous, and perfect God to love such creatures? To understand this we must understand something of the nature and character of God.
First John 4:8 and 16 tell us that “God is love.” Never was a more important declaration made than this—God is love. This is a profound statement. God doesn’t just love; He is love. His nature and essence are love. Love permeates His very being and infuses all His other attributes, even His wrath and anger. Because God’s very nature is love, He must demonstrate love, just as He must demonstrate all His attributes because doing so glorifies Him. Glorifying God is the highest, the best, and the most noble of all acts, so, naturally, glorifying Himself is what He must do, because He is the highest and the best, and He deserves all glory.
Since it is God’s essential nature to love, He demonstrates His love by lavishing it on undeserving people who are in rebellion against Him. God’s love is not a sappy, sentimental, romantic feeling. Rather, it is agape love, the love of self-sacrifice. He demonstrates this sacrificial love by sending His Son to the cross to pay the penalty for our sin (1 John 4:10), by drawing us to Himself (John 6:44), by forgiving us of our rebellion against Him, and by sending His Holy Spirit to dwell within us, thereby enabling us to love as He loves. He did this in spite of the fact that we did not deserve it. "But God demonstrates His own love for us in this: While we were still sinners, Christ died for us" (Romans 5:8).
God’s love is personal. He knows each of us individually and loves us personally. His is a mighty love that has no beginning and no end. It is this experiencing of God’s love that distinguishes Christianity from all other religions. Why does God love us? It is because of who He is: "God is love."