U.S. Attorney General Robert F. Kennedy (1925-1968) said at the Century 21 Exposition (Seattle World’s Fair) on August 7, 1962:
 
“We cannot stand idly by and expect our dreams to come true under their own power. The future is not a gift: It is an achievement. Every generation helps make its own future. This is the essential challenger of the present.”
 
‘The future is not a gift; it is an achievement” has infrequently (since about 1985) been credited to Scottish music hall and vaudeville theatre singer and comedian Harry Lauder (1870-1950), but there is no evidence that Lauder ever said it.
 
Similar sayings were said earlier. “Character is not a gift, it is an achievement” was cited in 1910. “Freedom is not a gift—it is an achievement” was also cited in 1910.  “Democracy is not a gift, it is an achievement” was cited in 1939.
 
       
Wikipedia: Robert F. Kennedy
Robert Francis “Bobby” Kennedy (November 20, 1925 – June 6, 1968), commonly known by his initials RFK, was an American politician from Massachusetts. He served as a Senator for New York from 1965 until his assassination in 1968. He was previously the 64th U.S. Attorney General from 1961 to 1964, serving under his older brother, President John F. Kennedy and his successor, President Lyndon B. Johnson. An icon of modern American liberalism and member of the Democratic Party, Kennedy was a leading candidate for the Democratic presidential nomination in the 1968 election.
 
Google News Archive     
28 January 1910, Florence (AL) Times, pg. 6, col. 3:
Character Building
“Character is not a gift, it is an achievement. One cannot inherit character or buy it with money. Character must be acquired through one’s one effort. It comes through choosing a rule of conduct. (...)”—Frank P. Cluver.
 
3 July 1910, Cleveland (OH) Plain Dealer, “Great is England; to Her a King is but a Symbol” by Elbert Hubbard, Plain Dealer Magazine, pg. 7, col. 5:
Canada prizes freedom quite as much as the states. Also, she has quite as much of the commodity as we have. Freedom is not a gift—it is an achievement.
 
Google News Archive
10 October 1939, Tuscaloosa (AL) News, “State Leader Sends Greetings” by Mrs. Carrie K. Andrews (President, Alabama Federation of B. and P. W. Clubs), pg. 11, col. 3:
Never have opportunities for service been greater. “Democracy is not a gift, it is an achievement” and we must continue to fight for it as did our ancestors many years ago.
     
11 May 1942, San Antonio (TX) Light, “March of Events” by Benjamin DeCasseres, pg. 12, col. 6:
This is he gist of what Jerome caused the nine professors at Colgate to say:
 
“Freedom is not a gift, but an achievement constantly won anew.”
(Colgate University senior William T. Jerome III, who inspired his professors to write The Spirit of Democracy.—ed.)
 
Google News Archive
1 May 1950, Pittsburgh (PA) Post-Gazette, “Strength For the Day” by Earl L. Douglass, pg. 12, col. 5:
If you want to get real satisfaction out of. life, get freedom; and if you want to get freedom, then be willing to pay the price of discipline. Freedom is not a gift; it is an achievement.
   
11 December 1950, Springfield (MA) Union, “Freedom and Hand-Outs” (editorial), pg. 6, col. 1:
A recent warning was made by Sen. Byrd when he said: “Let us always remember that human freedom is not a gift to man. It is an achievement by man, and, as it was gained by vigilance and struggle, so it may be lost by indifference and supineness.”
 
Google News Archive
17 January 1952, Prescott (AZ) Evening Courier, pg. 3, col. 2 ad:
MEMORABLE SAYINGS ABOUT THE PROBLEMS OF TODAY (No. 8 of a Series)
“Human freedom is not a gift of man. It is an achievement by man, and it may be lost by indifference.”
HARRY F. BYRD
U.S. Senator, Virginia
THE BANK OF ARIZONA
 
U.S. Department of Justice
ADDRESS BY
ATTORNEY GENERAL ROBERT. F. KENNEDY
SEATTLE WORLD’S FAIR
AUGUST 7, 1962
Pg. 2:
We cannot stand idly by and expect our dreams to come true under their own power. The future is not a gift: It is an achievement. Every generation helps make its own future. This is the essential challenger of the present.
 
Google Books
Rights for Americans;
The speeches of Robert F. Kennedy
By Robert F. Kennedy
Indianapolis, IN: Bobbs-Merrill
1964
Pg. 72:
And at the Seattle World’s Fair on August 7 he asked the members of his audience not to deceive themselves about the difficulties which lay ahead and then stated his conviction: “We cannot stand idly by and expect our dreams to come true under their own power. The future is not a gift: It is an achievement. Every generation helps make its own future. This is the essential challenge of the present.”
 
Google Books 
The Quotable Robert F. Kennedy
Edited by Sue G. Hall
Anderson, SC: Droke House; distributed by Grosset and Dunlap, New York, NY
1967
Pg. 84:
... The future is not a gift: it is an achievement. Every generation helps make its own future. This is the essential challenge of the present. (Address, Seattle World’s Fair, August 7, 1962).
 
Google News Archive
26 May 1984, Deseret News (Salt Lake City, UT), “Fire alarm interrupts Davis exercises,” pg. A13, cols. 4-5:
“The future is not a gift, it is an achievement,” a statement by President Kennedy, was the theme for the commencement.
 
Google News Archive
13 September 1986, The Free Lance-Star (Fredericksburg, VA), “Baliles on roads: Life should mean more than staring at car bumpers” by Gerald L. Baliles (Governor of Virginia), pg. 16, col. 6:
I believe in this transportation program because I believe in Virginians. They know that the future is not a gift, it is an achievement.
 
Google Books
No Aim, No Gain:
Aimless Life or Life of Aim¹Which Describes You
By Jeff Wickwire
Insight International Incorporated
1999  
Pg. 104:
Harry Lauder said, “The future is not a gift, it’s an achievement.”
 
WhiteHouse.gov
January 25, 2011
Remarks by the President in State of Union Address
United States Capitol, Washington, D.C.
9:12 P.M. EST
(...)
The future is ours to win. But to get there, we can’t just stand still. As Robert Kennedy told us, “The future is not a gift. It is an achievement.” Sustaining the American Dream has never been about standing pat. It has required each generation to sacrifice, and struggle, and meet the demands of a new age.
 
NewsBarb
Axelrod: A ‘Believer’ Politics is a Means to Confront Challenges, Improve the Future
Axelrod noted that, in his new book, “Believer: My Forty Years in Politics,” the premise behind the work is that politcs is about more than simply winning elections, it’s about securing the future. He added that he came to that belief at a very young age.
By Lucy Perry on 2/6/2015
(...)
In his concluding remarks, Axelrod told the audience at Tilson Auditorium that one of the reasons he was happy to be on the ISU campus was because he “ relishes the opportunity” to talk to young people, to encourage them to be “baton carriers” in the future.
 
“Because I’m very mindful of what Robert Kennedy said: ‘The future is not a gift, it’s an achievement. That’s why we do the work,” he said.