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Loving others, even one’s enemies is a teaching stressed on in most religions and sects. The Bible aside, this matter can also be found in Islam; in the supplications taught to us by the imams. In these supplicaltions, loving others has been emphasized greatly. To prove this calim, we will mention some Islamic teachings and Christian teachings as well.
The Bilbe says:
“But I tell you to love your enemies and ask for abundance for those who persecute you, do good to those who hate you and pray for those who slander you.” Two other passages can also be found in the Bible with similar themes.
It is interesting to know that passages similar to these can be found in Islamic supplications as well. For instance, in his supplication on noble moral traits and acts pleasing to God, Imam Sajjad (as) says:
These were only examples of Islamic and non-Islamic teachings on loving others.
But there is also a difference between Islam and Christianity regarding this subject. The question is:
Is all love, regardless of who the one being loved, and what the motive is, considered moral and good? Is morality only about loving others?
It is said that Christian scholars believe the only criterion ofr seeing if an act is moral or not, is to see if it has to do with love or not. This viewpoint is neither totally correct nor totally incorrect. One dimension of it is true, while the other is false and has problems:
1- Morality isn't always about loving others; for instance, defending oneself against oppression is also an instance of morality and moral conduct, yet it doesn’t fall under the category of loving others.
2- The concept of loving others; what does it really mean? Does it mean that we have to love anything categorized in science as human? What if a person has lost his/her humanity, do we still have to love him/her? Is it really okay for us to turn the blind eye to the oppression and sins of others in the name of love?
According to Islam, people who bear no moral traits still deserve to be loved, but only for them to be drawn towards these traits. Therefore, what is meant when it is said to love your enemy, is that you have to pull him towards goodness and morality, not that you have to prepare the grounds for further sinning. For example, if you have a friend that steals, since you like him, you first forbid and advise him. If he doesn’t heed, you frown at him, showing your dissatisfaction. If he still doesn’t listen, in order to help him, you will even take him to the police. So you can love someone and at the same time, discipline them.
It is on this basis that it has been said in hadiths that: "Religion is nothing but love and affection." When a sinner is punished, it is because he is loved and cared for; so that he might stop the bad act and return to his human self [rather than his animalistic desires]. Cases like these suggest that what truly deserves enmity and hatred, aren’t individuals, but bad actions are the true things to be hated and can be considered humanity's greatest threat and enemy.
As for your question about alcohol; what you said is totally true; alcohol is indeed a great enemy of man. The Quran and Islamic tradition both corroborate this fact. The prophet of Islam (pbuh) has been narrated saying: "Intoxicants are the mother of evil acts" and "Intoxicants are the origin of dirty acts" and "Intoxicants draw sins, are the mother of dirty things, and the key to bad acts."
You may have gotten the answer to your question through what was said till now, but to sum it all up, loving one's enemy is only to save him from his bad traits. It was also said that individuals themselves deserve to be loved, and it is their bad actions and traits that need to be hated. So loving the enemy has a disciplining side to it, which is for him to discontinue his badness; but since intoxicants are the key to many bad actions and sins, one must refrain from them and consider them the true enemy. Not only doesn’t consuming them help in the discontinuation of badness and sin, it greatly contributes to it.
Conclusion: The argument you mentioned isn’t acceptable, because what is meant by the word "enemy" is the person who when loved, corrects himself and discontinues his old ways (when we show love to such a person, we are actually showing hate to his bad actions and attributes, and we want them to perish, that is why we show love to the person himself). Intoxicants and alcohol which this argument says we have to love because they are our enemies, are harmful to us and our bodies and even to society; it can't be said that they have to be loved, because no one loves harmful things! If that was the case, we would have to love poison and the like by consuming them as well
 Matthew 5:44
 Luke 6:27; Luke 6:35.
 Mafatihul-Jinan, pg.997.
 What we mean by Christianity, is the religion preached by Christian preachers today, because there are always chances that religious scriptures might encompass certain things that the preachers of that religion might be unaware of.
 Murtadha Mutahhari, Falsafeye Akhlaq, pp.47-54.
 "َلِ الدِّینُ إِلَّا الْحُبُّ" Al-Kafi, vol.8, pg.80.
 Muhammad Muhammadi ReyShahri, Mizanul-Hikmah (translation), vol.4, pg.1545.