Means "Goodbye, Friend" translated from Hebrew.
Said by Bill Clinton on November 5, 1995 in his statement on Yitzhak Rabin's assassination the day after (November 4, 1995).
Since then became a popular phrase in Israel to express the loss, bumper stickers being it's most popular form (probably even the most popular bumper sticker in Israel).

Unfortunately, someone took things a little too far (in my opinion) the famous sticker experienced a bit of an evolution as new stickers of the same genre were introduced:

"Friend, You Are Missed" - ("Haver, Ata Haser")
"Friend, I Remember" - ("Haver, Ani Zoher")
"Friend, Time Goes By, But I Remember" - ("Hazman Over Aval Ani Zoher Haver")

I actually belive there was another one but I lost track.

Clinton's Statement:
The world has lost one of its greatest men - a warrior for his nation's freedom, and now a martyr for his nation's peace.

To Leah Rabin and her children, Hillary and I send our love and our prayers. To the people of Israel, I want you to know that the hearts and prayers of all Americans are with you. Just as America has stood by you in moments of crisis and triumph, so now we all stand by you in this moment of grieving and loss.

For half a century, Yitzhak Rabin risked his life to defend his country. Today he gave his life to bring it a lasting peace. His last act, his last words, were in defense of that peace he did so much to create. Peace must be and peace will be Prime Minister Rabin's lasting legacy. Tonight the land for which he gave his life is in mourning. But I want the world to remember what Prime Minister Rabin said here at the White House barely one month ago, and I quote: ``We should not let the land flowing with milk and honey become a land flowing with blood and tears. Don't let it happen.''

Now it falls to us, all those in Israel, throughout the Middle East and around the world who yearn for and love peace to make sure it doesn't happen. Yitzhak Rabin was my partner and my friend. I admired him and I loved him very much. Because words cannot express my true feelings, let me just say, shalom, haver - goodbye, friend.

Statement taken from: