“By this we know love, that he laid down his life for us, and we ought to lay down our lives for the brothers.” (1 John 3:16).
God calls us to love Him by loving our brethren in thought, word and deeds because He wants us to follow in His footsteps. In Jesus, God has shown His love for all mankind. He gave Himself up for us. We ought to do the same for Him, not out of obligation, or guilt or the desire to be liked or to do enough good to make it to heaven, but out of thankfulness for what He has one for us.
The major religions of the world do not believe in a loving God who dispenses mercy and unconditional grace. Almost every religion other than Christianity teaches that the good works of men, the righteous acts mankind performs will make them righteous and holy and one with God, or as in case of some such as Buddhists, make us one with the universe or universal spirit. Christianity teaches that such a thing is impossible for all men are sinners and incapable of pleasing God. No human is inherently righteous or holy. No human can perfectly perform good acts and deeds with pure motives.
God gives righteousness and holiness and the ability to perform good deeds to men. And whom does God choose to grant His favor to? To those who are noble and do good things or appear righteous, religious, rich or famous? No. He grants His favor to sinners, to the weak, the despised and the humble for only they realize their need for God. And why does He grant His favor to anyone at all? Because He loves us.