Greetings,
As a Christian we would start out saying it in a similar way-- we are saved through faith, but faith without works is dead, so both are then necessary. For the muslims they are saying that the hope and fear are essentially what drives the works-- hope of the future and fear of God. For a Christian, we also fear God and have a hope for the future, but for us the driving force behind the works would be love for God.
I do not see the main difference as being the implication that Christianity teaches its followers to love God more than Islam does. In Islam, love is also a huge driving force to do good. The more that a person loves Allaah (swt), the easier it becomes to do good deeds, no matter how difficult they might seem. The more a person loves Allaah (swt), the more he/she enjoys doing good deeds and going beyond what is required of them. This relates back to the other thread about prayer where it was mentioned how prayer is considered a comfort and relief and that communicating with Allaah (swt) is the joy of believers. Similarly, love of Allaah (swt) allows one to see fasting as a mercy and gift from Allaah (swt) by which we can return to Him through our observance of it. There are many examples from the pious predecessors of how they not only strove to do voluntary acts of obedience, but even enjoyed enduring the hardship involved to achieve the pleasure of Allaah (swt). Their statements attest to their extreme love of Allaah (swt). Taking the night vigil supererogatory prayer (Tahajjud) as an example:
Yazeed al-Riqaashi said: “A lot of Tahajjud brings delight to the worshippers, and a lot of thirst (i.e., fasting), brings joy when they meet Allaah.”
Abd-Allaah ibn Wahb said: “Every type of pleasure is enjoyed only once, except for acts of worship, which are enjoyed three times: when you do it, when you remember it, and when you are given the reward for it.”
Muhammad ibn al-Munkadir said: “There is nothing left of the joys of this life except three: qiyaam al-layl, meeting one’s brothers in faith, and praying in congregation.”
Thaabit al-Banaani said: “There is nothing I enjoy more than qiyaam al-layl (optional night prayer)”
That is not to say that hope and fear were not important elements driving such pious people to do good. But their level of devotion and attachment to Allaah (swt) and deriving pleasure from worship is an indication of how love must also have been a very powerful motive behind their deeds.
You will also note from the article posted by sister Insane Insaan that the very first verse in the Qur'an refers to the love of Allaah (swt):
All Praise [and Thanks] are for Allah, Rabb of all the worlds. [Al-Fatihah: 1]
When we acknowledge that Allaah (swt) has given us countless blessings, we are overwhelmed with love for Him and this leads to gratitude. And gratitude for blessings is a means of attaining the pleasure of Allaah (swt) which is the noblest situation of the people of Paradise. When the people of Paradise say, “You have given to us what You have not given to anyone among Your creation,” Allaah will say to them: “ Shall I not give you something better than that?” They will say, “What is it? Have You not brightened our faces, and admitted us to Paradise and saved us from Hell?” He will say,
“I bestow My pleasure upon you, and I will never be angry with you after that.” (Based on a hadeeth in Bukhari and Muslim).
Moreover, gratitude is expressed through using one's physical faculties in obedience and avoiding disobedience.
It was narrated that ‘Aa’ishah said: When the Messenger of Allaah (blessings and peace of Allaah be upon him) prayed, he would stand for so long that his feet became swollen. ‘Aa’ishah said: O Messenger of Allaah, are you doing this when Allaah has forgiven your past and future sins? He said: “O ‘Aa’ishah, should I not be a thankful slave?” [Narrated by al-Bukhaari (4557) and Muslim (2820)]
This is a very beautiful hadeeth showing how much love the Prophet (peace and blessings of Allaah be upon him), our example to be followed, had for Allaah (swt). Even though his past and future sins were forgiven, his love for Allaah (swt) and gratitude meant he continued to strive to be the most excellent slave he could be.
Love of Allaah (swt) is so important in Islam that it is actually one of the conditions upon which one's declaration of faith depends. That is,
to love all that the declaration of faith requires and all it implies, to love all those who act upon it and who hold to all that it stands for, and to feel anger at whatever contradicts it. Allah (swt) says:
And [yet], among the people are those who take other than Allah as equals [to Him]. They love them as they [should] love Allah . But those who believe are stronger in love for Allah . And if only they who have wronged would consider [that] when they see the punishment, [they will be certain] that all power belongs to Allah and that Allah is severe in punishment. [2:165]
And He (swt) says:
O you who have believed, whoever of you should revert from his religion - Allah will bring forth [in place of them] a people He will love and who will love Him [who are] humble toward the believers, powerful against the disbelievers; they strive in the cause of Allah and do not fear the blame of a critic. That is the favor of Allah ; He bestows it upon whom He wills. And Allah is all-Encompassing and Knowing. [5:54]
The Prophet, may Allah bless him and grant him peace, said, 'The sweetness of faith belongs to whoever may find himself in these three states: that Allah and His Messenger are more dear to him than any other thing; that he loves someone only for the sake of Allah; and that he despises a return to disbelief after Allah had saved him from it, as much as he would hate to be thrown into the fires of Hell.' (Bukhari and Muslim)
There are many other hadeeth and examples of the concept of love in Islam, but due to lack of time I hope the above will suffice for now.
Going back to the differences between Islam and Christianity... it is clear that both religions speak of love towards God. I would say a more accurate way of stating the difference is that Christianity chooses to only emphasise the concept of love, whereas Islam gives a more complete picture by balancing that love with fear and hope. Love is one aspect of worship, but not the only one. Let us consider the following quote from the Bible:
"There is no fear in love, but perfect love casts out fear. For fear has to do with punishment, and he who fears is not perfected in love". 1 John 4:18
It seems that Christians believe that loving God means not having any fear. They also seem to believe that even seeking God's forgiveness renders their love for Him ingenuine, and instead they should "enjoy a state of permanent forgiveness" for all that one may think or do. This is where it must be pointed out that love on its own becomes an extreme, to the extent that it gives one a false sense of security against God's Wrath. It opens the way for one to do as he pleases instead of doing what is required - submitting to God's Will.
On the other hand, Islam teaches us to have fear of Allaah (swt) which is beneficial for the heart. It is possible for such fear to co-exist with love. It is not only for the grave sinners but also for the pious worshippers who fear their deeds may not be accepted. Hence it has been said that "a believer combines righteousness with fear in his heart, while a hypocrite combines evil with impunity."
The following excerpt sheds a little light on the concept of fear in Islam and why it is important:
...Abu Hafs says, "Al-khawf (fear) is Allah's lash with which He straightens up those fleeing from His door." He also said, "Al-khawf is a lamp in the heart, with which the good and the evil inside of the heart can be seen-and everyone you fear from, you run away from him, except Allah-when you fear Him, you run towards Him for refuge."
Hence, the one who fears Allah is a refugee towards His Lord's [mercy] from his Lord's [displeasure].
Abu Suleiman said, "Whenever fear (of Allah) departs a heart, it is ruined." Ibraheem ibn Sufyan said, "When fear of Allah resides in hearts, it burns away the sources of lust and eradicates worldly attachments." Thun-Noon said, "People will stay on the path so long as they have (Allah's) fear when this fear leaves them, they will go astray."
Fear, however, is not the end in itself, but a means towards an end. When that end, Allah's ultimate pleasure, is attained, there is no need for fear. As Allah says to the people of Paradise: "there is no fear upon them, nor do they grieve."
Fear is associated with actions, while love is connected with being and attributes. When the believers enter the Realm of Allah's eternal blessings, their love will multiply, while their fear will disappear. Hence, the place of love is higher and nobler than the place of fear.
The true and praiseworthy fear is that which stops a person from the prohibitions of Allah. But when fear exceeds this boundary, it may bring hopelessness and despair.
Abu Uthman said, "Sincerity of fear is vigilance from sins, open and secret." I also heard Shaykhul Islam Ibn Taymiyyah, may Allah honor his soul, say, "The praiseworthy fear is that which prevented you from the prohibitions of Allah."
The author of al-Manazil, Shaykh al-Harawi, said, "Al-khawf, or fear, is to do away with careless sense of security by envisioning the great news (of the Last Day)."
http://www.islaam.com/Article.aspx?id=664
The Qur'an mentions the examples of Prophets and pious people who worshipped Allaah by combining fear with hope. Insha'Allaah we can discuss the concept of fear in Islam in more detail later if required.
And Allaah (swt) knows best.
I end with the following poem by the famous Islamic scholar, may Allaah (swt) have mercy upon him, Ibnul Qayyim al Jawziyyah:
Love of Allah
The love of the Beloved
must be unconditionally returned.
If you claim love
yet oppose the Beloved,
then your love is but a pretence.
You love the enemies of your Beloved
and still seek love in return.
You fight the beloved of your Beloved.
Is this Love or the following of shaytaan?
True devotion is nothing
but total submission
of body and soul
to One Love.
We have seen humans claim to submit,
yet their loyalties are many.
They put their trust here, and their hope there,
and their love is without consequence.