All the teachings of Islam are based on two basic principles - worship of God and service of men. Without putting both of these principles into practice, there can be no true fulfillment of one's religious duties. In its followers, Islam inculcates the spirit of love and respect for all human beings. By serving human beings on the one hand they please their God, and on the other they achieve spiritual progress for themselves. According to a hadith, you should be merciful to people on earth and God on high will be merciful to you. In this way Islam links personal salvation to serving others. One can receive God's reward in the Hereafter only if one has done something to alleviate the sufferings of mankind. According to a hadith on Doomsday God will say to a person, "I was ill, but you did not come to nurse Me." The man will reply, "God, You being the Lord of the universe how can You be ill?" God will answer, "Such and such servant of Mine was ill. Had you gone there, you would have found Me there with him." Then God will say to another person, "I was hungry, but you did not feed Me." The person will reply, "God, You are the Lord of the worlds, how could You go hungry?" God will say, "Such and such of my servant came to you, but you did not feed him. Had you done so, you would have found Me with him." Then God will say to yet another man, "I was thirsty, and you did not give Me water to drink." That person will also say, "God, You are the Lord of the worlds, how could You be thirsty?" God will say, "Such and such servant of Mine came to you, but you did not give him water to drink. Had you offered him water, you would have found Me there with him." From this, we learn the Islamic principle that if someone wants to find God, he shall first have to make himself deserving of this by helping the poor and the needy. This act becomes a means of spiritual progress for him. And there is no doubt about it that it is only those people who have elevated themselves spiritually, who will find God. This culture of mercy and compassion approved of by God is not limited to human beings, but extends also to the animal world. We must be equally sympathetic to animals. The Hadith gives us many guidelines on how to look after animals and treat them with fairness. There are duties laid down by God. One who is cruel to animal's risks depriving himself of God's mercy.