Crisp fall winds assault the fading foliage on Riverside Drive. A glittering Hudson is backdropped by New Jersey's imposing Palisades. On the New York side sits a magnificent cathedral - the Riverside Church - where, historically, sermons of peace and light have echoed the strains of religious freedom on which this nation was founded.
But such grandeur belies a black and Hispanic ghetto that knows hunger and poverty and crime. New York's Upper West Side, long a symbol of white middle-class affluence, now carries a logo of minority despair. Harlem-spawned homicide and drug-dealing splash across Broadway making this a high-risk area.
Spanning these two worlds of the pastoral and poor is one of the nation's most unorthodox and controversial clergymen: William Sloane Coffin, senior minister at Riverside Church.
The Rev. Mr. Coffin, an ordained Presbyterian, has been preaching a sermon of social activism and political reform for more than two decades, first as chaplain at Yale University, and for the past eight years here on the banks of the Hudson.
Today, as yesterday when he marched with ''Freedom Riders'' in the South and struck piercing chords against Vietnam and the draft, Bill Coffin is still fighting the ''Establishment'' with words from the pulpit and movement among the masses.
But now the police confrontations, the arrests for civil disobedience, and the bitter exchanges with more traditional defenders of the faith that marked his early career have faded into the background. In some quarters, the graying but still zestful, let-it-all-hang-out clergyman remains a ''heretic'' and ''communist sympathizer.'' However, even his most vitriolic detractors have lowered their voices.
Coffin himself doesn't seem to mind being out of the political spotlight. But he objects to being considered ''mellowed.'' His interpetation of Christianity is still intertwined with confrontation. He insists that, over the years, he has become ''more impatient and more compassionate.''
The clergyman's ''impatience'' these days centers around two themes: nuclear disarmament and sharing the wealth.
Coffin has two deep concerns about Americans' attitudes toward nuclear war: One is that the whole idea is so awesome, people don't really think they can do anything about it - hence they are apathetic. The other involves ''power.''
''The one thing we Americans are not about to give up is power,'' he says. ''And I'm afraid the devil is seducing us to seek status through power.''
''Instead of the devil we should be heeding the Psalmist: 'The war horse is a vain hope for victory, and by its great might it cannot save,' '' he counsels.
''Instead of escalating the arms race, we should be doing everything we possibly can to slow, stop, and reverse it. This is the meat-and-potatoes issue of our day, and it is on the plate of every Christian'' is Coffin's most potent antinuclear message from the pulpit.
If some view the minister's disarmament stance as rebellious, his ideas about economic and social equality would fall into the revolutionary category. Coffin doesn't particularly like the word ''revolutionary,'' especially when it refers to him. Almost defensively, he quotes President John F. Kennedy: ''Those who make peaceful evolution impossible make violent revolution inevitable.''
Coffin heartily supports human rights movements in Central America. Last year , he was a key contributor to a conference on Nicaragua whose theme was ''Saying No to Reagan's Wars.''
Sometimes accused of being ''soft'' on communism or playing directly into the hands of America's antagonists, Coffin responds: ''It must be understood that communists don't make revolutions. Bad governments make revolution. . . . The Gospel has more to do with most Latin American revolutions than Marxism does.''
As a Christian, Coffin says he is committed to ''bloodless'' revolutions. ''It's up to the church to keep these confrontations nonviolent and motivated by love of the good rather than hatred of evil,'' he explains.
The liberal pastor is no more timid today in expounding his social philosophy than he was in the '60s when his civil disobedience over civil rights and the draft led to several arrests.
''I believe that the redistribution of wealth - at home and abroad - should be at the top of the agenda of every American church,'' he writes in his current book, ''The Courage to Love.''
''So I would urge my fellow clergy to plead without ceasing the cause of the oppressed. Preachers need to remind their people that 'all members of the body, though many, are one body,' that to know God is to love the poor,'' he adds. Coffin maintains that by bringing a degree of justice to the poor, the rich also gain ''a measure of salvation.''
He points to a second-century manual on church discipline, which addresses well-to-do Christians in this manner: ''If you are willing to share what is everlasting, you should be that much more willing to share things which do not last.''
In his ''it's the rich that make the poor'' philosophy, Coffin seems to block out what many Christians believe is the responsibility mankind has for its own welfare.
The Protestant pastor's social beliefs translate into social action via Riverside Church's often heralded - but sometimes criticized - community food program. ''We serve free food for two hours a day. But it's a scandal that we should have to do this,'' the pastor says.
''There should be no hungry people in the richest country in the world. We need to point this out at all times.''
''Charity is no substitute for justice,'' the minister stresses. ''And food, in my mind, is a matter of justice, not a matter of charity.''
However, he quickly adds: ''We can engage in charity while at the same time we are advocates of justice.''
When Bill Coffin isn't preaching social justice, feeding people, or warring against the nuclear movement, he is fighting off the Religious Right. The latter tend to write him off as an ''infidel'' and lampoon him in their literature.
On the other hand, the liberal pastor scores the Moral Majority and other fundamentalist religious groups for playing on the fears of the public. ''The opposite of love is not hate, but fear'' is a favorite Coffin theme. He hastens to invoke the Scripture: ''Perfect love casteth out fear.''
He insists that the Rev. Jerry Falwell, leader of the Moral Majority, gives people what they want, not what they need.
''Falwell presents religion as a haven from insecurity,'' Coffin says, ''whereas true religion is what makes it possible for an individual to take on all the insecurity in the world.
''He has all the answers. True religion makes sure you have all the questions ,'' he says.
Although Coffin constantly warns his parishioners - and anybody else who will listen - about the ''finality'' of war and the dire consequences of social inequality, he insists he is not a fatalist. He says his deep faith relieves him of despair.
He also doesn't see the ''church'' openly and broadly embracing the social philosophy and involvement that he preaches. ''To expect the average establishment suburban church to take the lead in matters of social justice and redistributing the wealth would be naive'' Coffin admits.
''Basically, the pressure to redistribute wealth will come from the bottom of society, not from the top. The church, if it's made up of poor people, will be in the forefront. If it's made up of rich people, I hope it will cooperate more gracefully with the inevitable by virtue of being a church.''
Reverend Coffin adds that although he sees social reform as God-ordained, it is not the exclusive province of the church. He quotes St. Augustine: ''There are as many sheep outside the fold as there are wolves within.''
And with that rebel grin one remembers from yesteryear, he adds: ''I look for the sheep outside the fold to help offset the wolves within.''