Love is the central theme of the Bible. If we read it from cover to cover, it revolves around the story of how God loves mankind despite the fact that he does not want to do anything with Him. God gave men through the ages chances to be reconciled to Him, to no avail.
Finally, He sent His only begotten Son to pay for the sins of the world, and that all may have hope. This sacrifice by both the Father and the Son are the ultimate illustrations of unconditional love in the Bible. Anyone who believes in Jesus would receive this love, and the promise of eternal life.
Once a person gets saved and promised a home in heaven, it is his turn as a Christian to emulate the same love he has received from Christ.