Making Dua - May Allah [...] in sha Allah

[Insaanah]

Sometimes, when people wish something for someone or make a du'aa for them they say, "May Allah grant [thing to be granted here] in shaa Allah", or, "may Allah [do such and such] in shaa Allah".

One of the etiquettes of du'aa is to determined in one's request.

Anas ibn Malik :ra: narrates that the Prophet :saws: said:

"When one of you makes a du'aa, then let him be firm and determined in his du'aa and let him not say, "O Allah! If You will, then please forgive me', for there is no one who can force Allah to do anything".

In another very similar hadith, Abu Huraira :ra: narrated:

Allah's Messenger (ﷺ) said, "None of you should say: 'O Allah, forgive me if You wish; O Allah, be merciful to me if You wish,' but he should always appeal to Allah with determination, for nobody can force Allah to do something against His Will."

http://sunnah.com/bukhari/80/36 (Bukhari)
http://sunnah.com/muslim/48/7 (Muslim)
http://www.sunnah.com/abudawud/8/68 (Abu Dawud)
http://www.sunnah.com/urn/404970 (Muwatta Malik)

Therefore, what is desired is that a person be firm in his du'aa, asking from Allah in a determined manner. If, on the other hand, a person says, "O Allah! Grant me my du'aa if you wish", this goes against the firmness and resolution that is desired. A person is always in need of Allah's help and aid, and as such should always ask of Allah in a manner that shows his poverty for Allah's support.

It should be pointed out that it is allowed to use this phrase "if you wish" or similar, when the person does not know if the matter he is asking for is for his good or not. So, it is permissible to pray: "O Allah! If you know that such-and-such a matter (related to this world) is good for me, then grant it to me." What is prohibited is to use this phrase in matters that one needs without a doubt, such as Allah's Forgiveness, or Mercy, or Blessings, etc.

(Adapted from Dua, weapon of the believer, a treatise on the status and etiquette of Dua in Islam, by Abu Ammaar Qadhi)

PDF available here: http://www.allahsword.com/ebooks/Supplications/Dua The Weapon Of The Believer.pdf

And let us not forget aameen at the end of our du'aas.