Assalam AlaikumWhat is the ruling on a person Which says to his girlfriend/boyfriend that he/she only lives for him/her.Because We live only for Allah So Is it a kind of major Kufr. Or What if someone sings a song contains these lines like

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

In Islam, there are limits for the words that a Muslim utters, and Islam forbade a number of words whose literal meaning is an exaggeration in religion, especially with regard to glorifying Allah and Tawheed [testifying that None has the right to be worshipped but Allah, and worshipping Him Alone], even if the speaker himself did not intend the prohibited meaning.

For example, it is forbidden in Islam to say to a slave ‘feed your Rubb’ (which literally means your master and your owner). It is known that in the Arabic language, the word “Rubb” refers to Allah and it can also refer to the master (i.e. the owner) of the slave, the owner of the house [landlord], and so forth. Therefore, it is forbidden in the Sharee’ah to use this common term that has these various meanings, as a way of guarding Tawheed and preventing Shirk and exaggeration.

Ibn Al-Qayyim said: “He [The Prophet ], forbade a man from saying to his servant ‘perform ablution to your Rubb’; ‘feed your Rubb’ as a way of warding off Shirk in regard to both the wording and meaning, although the word “Rubb” here means the owner, like the owner of the house [landlord], the owner of the camels […] he forbade saying the word Rubb to the master (owner) as a way of guarding Tawheed and warding off Shirk.” [End of quote]

There is no doubt that the apparent meaning of the phrase (I live for you) is an exaggeration in loving other than Allah, and it negatively affects one’s Tawheed because a person is created to worship Allah Alone, and not to live for anyone other than Him; Allah Says (what means): {And I did not create the jinn and mankind except to worship Me.} [Quran 51: 56]

However, the mere utterance of this expression, whether one initiated it (said it) himself), or relating it from others –without believing in its literal false meaning –does not reach the level of Kufr (disbelief) at all.

It should be noted that there is another prohibition in this issue, which is that a man should not have such a relationship with a woman outside a valid Islamic marriage and that the sexual relation that happens as a result of such a relationship is Zina (fornication or adultery) as confirmed in an authentic Hadeeth.

Allah knows best.