Ibn Al-Qayyim (may Allaah have mercy on him) said regarding this matter:
There are four kinds of love, which we must differentiate between, and those who go astray do so because they do not make this distinction. The first of them is love of Allaah, but this alone is not sufficient to save a person from the punishment of Allaah and to earn him His reward. The Mushrikeen, worshippers of the cross, Jews and others all love Allaah. The second is love of that which Allaah loves. This is what brings a person into Islam and out of Kufr. The most beloved of people to Allaah is the one who is most correct and most devoted in this kind of love. The third kind is love for the sake of Allaah, which is one of the essentials of loving that which Allaah loves. A person's love of that which Allaah loves cannot be complete until he also loves for the sake of Allaah. The fourth is love for something alongside Allaah, and this love has to do with shirk. Everyone who loves things alongside Allaah but not for the sake of Allaah has taken that thing as a rival to Allaah. This is the love of the Mushrikeen. There remains a fifth kind of love which has nothing to do with our topic; this is the natural love which is a person's inclination towards that which suits his nature, such as the love of a thirsty person for water or of a hungry person for food, or the love of sleep, or of one's wife and children. There is nothing wrong with this unless it distracts a person from remembering Allaah and keeps him from loving Him. Allaah says (interpretation of the meanings):
"O you who believe! Let not your properties or your children divert you from the remembrance of Allaah" [al-Munaafiqoon 63:9]
"Men whom neither trade nor sale (business) diverts from the remembrance of Allaah" [al-Noor 24:37]
(Al-Jawaab al-Kaafi, 1/134)
And he said (may Allaah have mercy on him):
The difference between loving for the sake of Allaah and loving something alongside Allaah is one of the most important distinctions. Everyone needs to make this distinction and is indeed obliged to do so. Loving for the sake of Allaah is a sign of the perfection of faith, but loving something alongside Allaah is the essence of shirk. The difference between them is that a person's love for the sake of Allaah is connected to his love of Allaah; if this love becomes strong in his heart, this love dictates that he will love that which Allaah loves. If he loves that which his Lord loves and he loves those who are the friends of Allaah, this is love for the sake of Allaah. So he loves His Messengers, Prophets, angels and close friends because Allaah loves them, and he hates those who hate them because Allaah hates those people. The sign of the love and hatred for the sake of Allaah is that his hatred for the one whom Allaah hates will not turn into love merely because that person treats him kindly, does him a service or meets some need he has; and his love for those whom Allaah loves will not turn to hatred simply because that person does something that upsets or hurts him, whether it is done by mistake or deliberately, in obedience to Allaah or because the person feels that he has a duty to do it for some reason, or because the person is a wrongdoer who may yet give up his wrongdoing and repent. The entire religion revolves around four principles: love and hatred, and stemming from them, action and abstinence. The person whose love and hatred, action and abstinence, are all for the sake of Allaah, has perfected his faith so that when he loves, he loves for the sake of Allaah, when he hates, he hates for the sake of Allaah, when he does something, he does it for the sake of Allaah, and when he abstains from something, he abstains for the sake of Allaah. To the extent that he is lacking in these four categories, he is lacking in faith and commitment to religion. This is in contrast to the love of things alongside Allaah, which is of two types. One is diametrically opposed to the principle of Tawheed and is shirk; the other is opposed to perfection of sincerity and love towards Allaah, but does not put a person beyond the pale of Islam.
The first kind is like the love of the Mushrikeen for their idols and gods. Allaah says (interpretation of the meaning):
"And of mankind are some who take (for worship) others besides Allaah as rivals (to Allaah). They love them as they love Allaah" [al-Baqarah 2:165]
These Mushrikeen love their idols and gods alongside Allaah as they love Allaah. This love and devotion is accompanied by fear, hope, worship and supplication. This love is pure Shirk which Allaah does not forgive. Faith cannot be perfected unless a person regards these idols as enemies and hates them intensely, and hates the people who worship them, and regards them as enemies and strives against them. This is the message with which Allaah sent all His Messengers and revealed all His Books. He created Hell for the people of shirk who love these rivals, and He created Paradise for those who strive against them and take them as enemies for His sake and to earn His Pleasure. Anybody who worships anything from the vicinity of the Throne to the lowest depths of the earth and takes a god and a supporter besides Allaah and associates another beings in worship with Him, will be disowned by the object of his worship when he is most in need of it [i.e., on the Day of Judgement].
The second kind is love for the things which Allaah has made attractive to people, such as women, children, gold, silver, branded beautiful horses, cattle and well-tilled land. People love them with a kind of desire, like the love of the hungry person for food and the thirsty person for water. This love is of three kinds. If a person loves them for the sake of Allaah and as a means of obeying Allaah, he will be rewarded for that; it will be counted as a part of love for the sake of Allaah and a means of reaching Him, and he will still find enjoyment in them. This is how the best of creation [i.e. the Prophet (peace and blessings of Allaah be upon him)] was, to whom women and perfume were made dear in this world, and his love for them helped him to love Allaah more and to convey His Message and fulfil His commands. If a person loves them because they suit his nature and his own desires, but he does not give them preference over that which Allaah loves and is pleased with, and he gets them because of his natural inclination, then they come under the heading of things which are permissible, and he will not be punished for that, but his love of Allaah and for the sake of Allaah will be lacking somewhat. If his sole purpose in life is to get these things, and he gives priority to that over that which Allaah loves and is pleased with, then he is wronging himself and following his own desires.
The first is the love of al-Saabiqoon (those who are foremost in Islam); the second is the love of al-muqtasidoon (those who are average) and the third is the love of al-zaalimoon (the wrongdoers). Al-Rooh by Ibn al-Qayyim, 1/254.
May Allaah bless our Prophet Muhammad.