My Young Daughter Constantly asks me, ‘Why can’t we see Allah in this life?’ – Shaykh Saalih Al-Fawzan
An Exclusive Translation for Sisters Upon Al-Istiqaamah
Shaykh Al-Fawzan was asked on behalf of a young girl the following question: 
My young daughter constantly asks me, ‘Why can’t we see Allah in this life?’ What is the best answer to give her as she is young?
The Shaykh (May Allah preserve him) said,
Say to her, ‘This is because you are not able to see him [in this life]. You would burn to pieces.’ It is not possible for a created being to see Allah in this life. Whereas in the Hereafter Allah gives the believer the strength and ability so he is able to see Allah. Yes.
In another place Shaykh Al-Fawzan mentions: 
“The Jahmiyyah and the Mu’tazilah, all of them, reject Ar-Ru’yah (the seeing of Allah) in the Hereafter. Another group exists who say, ‘Verily Allah is seen in this life and in the Hereafter.’ This is a position that is held by some of the Sufis.
The third position, and this is the true and correct stance, is that Allah, the Mighty and Majestic will be seen in the Hereafter by the people of paradise as is found in the ahadeeth that have been narrated upon the Prophet (peace and blessings be upon him) and which have reached the level of Mutawaatir (such a great number of ahadeeth it is not possible that they have all been invented). However, in this life, then verily Allah cannot be seen because the people cannot endure and survive seeing Him, the Exalted in this life. When Moosa (peace and blessings be upon him) asked to see Allah, the Exalted, in this life, Allaah said:
“And when Moses arrived at Our appointed time and his Lord spoke to him, he said, “My Lord, show me [Yourself] that I may look at You.” [Allāh] said, “You will not see Me, but look at the mountain; if it should remain in place, then you will see Me.” But when his Lord appeared to the mountain, He rendered it level, and Moses fell unconscious. And when he awoke, he said, “Exalted are You! I have repented to You, and I am the first of the believers.” [Al-A’raaf: 143]The solid mountain became dust due to the Greatness of Allah, the Mighty and Majestic. So how can a human being withstand seeing Allah [in this life]?”
Taken from http://uponistiqaamah.blogspot.com