Undated (AP) _ A few thousand carefully chosen speakers summed up a lifetime's lessons for those just starting out in commencement addresses at college campuses across the land this spring.

The ritualistic exercise offered a mix of advice and observation, anecdote, heart-felt emotion, droll humor.

The speeches reaffirmed society's ideals; chastised on-campus trends; pleaded on behalf of causes, nations and civil rights; girded those fearful of roads that lie ahead; and reminded teachers of their obligation to inspire and students of their duty to give back the benefits of a college education.

Here are excerpts from some of those speeches.

---

''Unless universities take their social responsibilities seriously, they will never inspire their students with a purpose large enough to fill their lives with meaning. Harvard has a special obligation to give generously of its ability and imagination to the society that sustains it.''

- Harvard University president, Derek C. Bok, in his last commencement address as head of the nation's oldest university.

---

''We have to make structural and innovative changes in how our families are managed, how jobs are designed, how educational systems are designed and in our cultural and institutional attitudes towards women and minorities.''

- Supreme Court Justice Sandra Day O'Connor speaking at Widener University. ---

''As law graduates, each of you now has the training to be an effective advocate on behalf of your fellow citizens, your community, and the principles in which you believe.''

-Secretary of State James A. Baker III speaking at South Texas College of Law.

---

''It is perplexing that the general call to ecumenical understanding is resulting on some college campuses in the most obdurate separatism since the 16th century.''

- Columnist William F. Buckley, speaking at Grove City College.

---

''We've demonstrated that the world's democracies can organize themselves to turn back aggression. We've proven that our democracy - a very special one that brings together men and women from a diversity of backgrounds - can function with the utmost grace under pressure.''

- Defense Secretary Dick Cheney speaking at Colorado College.

---

''It is very much in the interest of all Americans and of all people of good will on this Earth that we should be successful in what we undertake in the Soviet Union.''

- Former Soviet Foreign Minister Eduard Shevardnadze speaking at Emory University.

---

''You've had four years of hell and there's just no piece of paper to describe that. And you have no idea what you're going into. But you do have a great head start.''

- Baseball hall of famer Willie Mays speaking at Bowling Green State University.

---

''What is needed is a campaign for humanity. Europe is moving toward peace. West and East are stopping the arms race and the senseless waste of resources. We must now stop man's war on nature as well.''

- Germany's foreign minister, Hans-Dietrich Genscher speaking at the University of South Carolina.

---

''Your generation must bring about a reawakening of the spirit of community.''

- Virginia Gov. L. Douglas Wilder speaking at the University of North Carolina.

---

''We don't need another Great Society with huge and ambitious programs administered by the incumbent few. We need a Good Society, built upon the deeds of the many, a society that promotes service, selflessness and action.''

- President George Bush speaking at the University of Michigan.

---

''We returned to that country (Kuwait) the most precious gift anyone can give, the gift of liberty. Kuwait is free of Iraqi control because the United States is still the home of the brave.''

- Gen. H. Norman Schwarzkopf, the first Army officer invited to speak at the U.S. Naval Academy.

---

''Do not be afraid when you suffer. Remember that full pessimism is no less stupid than full optimism.''

- Soviet poet Yevgeny Yevtushenko speaking at Juniata College.

---

''People who live under tyranny are not responsible for the abuses committed by dictators. People who live in a democracy share the mistakes and victories of their leaders.''

- Former president of Costa Rica Oscar Arias Sanchez, recipient of the 1987 Nobel Peace Prize. speaking at Washington University in St. Louis.