According to the Quran this life has a purpose. That purpose is to pass a test devised by God to see which ones of us will serve Him and which ones of us will choose otherwise. This purpose for this life can be found throughout the Quran. Here are some of the relevant verses:
Drivers of the Winds 51:56
I did not create the jinns and the humans except to worship Me alone.
Muhammad 47:31
We will certainly put you to the test, in order to distinguish those among you who strive, and steadfastly persevere. We must expose your true qualities.
The Human 76:2
We created the human from a liquid mixture, from two parents, in order to test him. Thus, we made him a hearer and a seer.
The Prophets 21:35
Every person will taste death, after we put you to the test through adversity and prosperity, then to us you ultimately return.
Smoke 44:30-33
Meanwhile, we saved the Children of Israel from the humiliating persecution. From Pharaoh; he was a tyrant. We have chosen them from among all the people, knowingly. We showed them so many proofs, which constituted a great test.
The Cave 18:7
We have adorned everything on earth, in order to test them, and thus distinguish those among them who work righteousness.
S. 38:34
We thus put Solomon to the test; we blessed him with vast material wealth, but he steadfastly submitted.
The Arragers 37:104-106
We called him: O Abraham. You have believed the dream. We thus reward the righteous. That was an exacting test indeed.
The Spider 29:2-3
Do the people think that they will be left to say, "We believe," without being put to the test? We have tested those before them, for God must distinguish those who are truthful, and He must expose the liars.
Al-Hijr Valley 15:85
We did not create the heavens and the earth, and everything between them, except for a specific purpose. The end of the world will come, so treat them with benign neglect.
The Bee 16:92
Do not be like the knitter who unravels her strong knitting into piles of flimsy yarn. This is your example if you abuse the oaths to take advantage of one another. Whether one group is larger than the other, God thus puts you to the test. He will surely show you on the Day of Resurrection everything you had disputed.
The Believers 23:30
These should provide sufficient proofs for you. We will certainly put you to the test.
Jonah 10:14
Then we made you inheritors of the earth after them, to see how you will do.
T.H. 20:90
And Aaron had told them, "O my people, this is a test for you. Your only Lord is the Most Gracious, so follow me, and obey my commands."
The Heifer 2:155
We will surely test you through some fear, hunger, and loss of money, lives, and crops. Give good news to the steadfast.
T.H. 20:85
He said, "We have put your people to the test after you left, but the Samarian misled them."
Hood 11:7
He is the One who created the heavens and the earth in six days earthly domain was completely covered with water - in order to test you, to distinguish those among you who work righteousness. Yet, when you say, "You will be resurrected after death," those who disbelieve would say, "This is clearly witchcraft."
Jonah 10:47
To each community, a messenger. After their messenger comes, they are judged equitably, without the least injustice.
Jonah 10:5
He is the One who rendered the sun radiant, and the moon a light, and He designed its phases that you may learn to count the years and to calculate. God did not create all this, except for a specific purpose. He explains the revelations for people who know.
Ultimatum 9:44
Those who truly believe in God and the Last Day do not ask your permission to evade the opportunity to strive with their money and their lives. God is fully aware of the righteous.
Ultimatum 9:16
Did you think that you will be left alone without God distinguishing those among you who strive, and never ally themselves with God's enemies, or the enemies of His messenger, or the enemies of the believers? God is fully Cognizant of everything you do.
The Spoils of War 8:28
You should know that your money and your children are a test, and that God possesses a great recompense.
The Purgatory 7:168
We scattered them among many communities throughout the land. Some of them were righteous, and some were less than righteous. We tested them with prosperity and hardship, that they may return.
The Feast 5:94
O you who believe, God will test you with some game within reach of your hands and your arrows (during pilgrimage) God thus distinguishes those among you who observe Him in their privacy. Those who transgress after this have incurred a painful retribution.
The Heifer 2:214
Do you expect to enter Paradise without being tested like those before you? They were tested with hardship and adversity, and were shaken up, until the messenger and those who believed with him said, "Where is God's victory?" God's victory is near.
The Heifer 2:155
We will surely test you through some fear, hunger, and loss of money, lives, and crops. Give good news to the steadfast.
The Heifer 2:21
O people, worship only your Lord - the One who created you and those before you - that you may be saved.
Thanks to http://www.masjidtucson.org/ for permission to use Rashid Kalifa's translation of the Holy Quran.