I was in the middle of teaching tawhid when one of the students asked me about someone who asks for something in the name of Allah and His Messenger, and someone saying, "I am giving this for the sake of Allah and His Messenger," so I told him that is not permissible. So he replied that in the long hadith about the story of Ka`b ibn Malik related in Riyad as-Saliheen that he, meaning Ka`b ibn Malik (may Allah be pleased with him) told the Messenger of Allah (may Allah bless him and grant him peace), when he was informed that Allah had accepted his repentance and that of the two other men in his situation, he said, "O Messenger of Allah, verily, it is part of my repentance that I am giving up my money for the sake of Allah and His Messenger.

First of all: About asking in the name of Allah, the Mighty and Majestic

It has been related that "Nothing should be asked for by the Face of Allah, except Paradise." The scholars of hadith have declared this hadith weak (da`if), but supposing it to be true, scholars have disagreed over the intended meaning, according to two opinions:

The first opinion is that it means: do not ask any created being by the Face of Allah. If you want to ask one of the created beings, do not ask by the Face of Allah, because nothing should be asked for by the Face of Allah except Paradise and created beings do not have the power to grant Paradise; therefore, no one should be asked by the Face of Allah at all. However, when someone is asked by the Face of Allah, he should respond to the asker because of the hadith related from the Prophet (may Allah bless him and grant him peace), "Cursed is the one who asks by the Face of Allah and cursed is the one who is asked by the Face of Allah and then refuses to give the asker, as long as he does not ask for anything bad." [Related by at-Tabarani] Al-`Iraqi said, "Its chain of narrators is good (hasan) and the great sheikh, al-Albani also declared it good in Sahih at-Targhib (853, 851).

The second opinion is that, if you ask Allah, asking Allah for Paradise and whatever it takes to enter it, then there would be nothing wrong with asking by the Face of Allah. And if you ask for any worldly benefit, do not ask by the Face of Allah, for the Face of Allah is too great for anyone to ask for any worldly thing. So, anything concerning the Hereafter can be asked for by the Face of Allah, as for instance, saying, "I ask You by Your Face to save me from the Hellfire." The Prophet (may Allah bless him and grant him peace) sought refuge by the Face of Allah upon the revelation of the saying of Allah, {Say: "He has the power to send torment on you from above…}[Al-An`am 6:65] He said, "I seek refuge with Your Face." {…or from under your feet…} He said, "I seek refuge with Your Face." {…or to cover you with confusion in party strife and make you taste the violence of one another.} He said, "This is lighter and easier." 

If it is said that it carries both meanings, this would be a point. Mentioning Paradise would then be to use it as a warning about great, important matters, not itself in particular, such that one should not ask by Allah`s Face for anything trivial, as opposed to important things, whether to get something or to keep something away, as pointed to in the hadith about the Prophet (may Allah bless him and grant him peace) seeking refuge.

It would not be suitable, then, to ask by Allah`s Face, except for Paradise and whatever it would take to enter it, so the person asking should be made aware of that.

Secondly: On asking in the name of Allah and His Messenger in terms of tawhid (pure monotheism) and shirk (association in worship)

It is said that this expression is general: If the intention is to obey Allah and His Messenger—and this is the meaning carried in the words of Ka`b ibn Malik—this would be the first thing that comes to mind. If, on the other hand, the intention is to associate anything in terms of the object or form of worship, then this is the shirk (idolatry) about which people must be warned and made aware, although this meaning is quite distant; and Allah Almighty is more exalted and more knowledgeable.