RAY Kiely did not want to quit working when he retired from his quiet ministry in Grosse Pointe, Mich., last year. So he and his wife, Martha, decided on the ultimate adventure. Last October they moved to Beirut, arriving just two days before a truck-bomb killed 241 United States marines.
The threat to US citizens has heightened dramatically since mid-January with the kidnapping of three prominent Americans (a professor, a diplomat, and a television correspondent), the killing of the president of Beirut's American University, and the attempted assassination of a Marine colonel.
''Now,'' Dr. Kiely says, ''if I go out to lunch, I'm taking a risk. For the time being I'm putting a haircut off.''
There are an estimated 1,500 Americans still living in the Lebanese capital, people whom US officials concede have become virtual hostages to the situation. Like many other US citizens who are sticking it out in the troubled nation, the Kielys lay the blame squarely on US policy.
Dr. Kiely came to Beirut to take the job of president at the prestigious Near East School of Theology. The 148-year-old school, the only Protestant seminary in the Middle East, is vulnerable because its staff is largely American. For instance, unidentified assailants recently threw a grenade at the front of the modern structure in west Beirut, shattering the windows.
Despite the fighting and bombings, the kidnappings and killings, many American civilians still here say they intend to stay. John Cronin arrived shortly after the end of the Shouf mountain battles last fall to start a master's program in Middle East studies at American University. Despite the dangers, he felt that understanding the atmosphere and people of the region was as important as the academic training.
Mr. Cronin, a former marine and Vietnam veteran, admitted he has become ''circumspect about my movements off-campus. I don't walk around in the dark.''
Yet somehow someone managed to penetrate security guards around the walled university grounds to plant a bomb that went off in an empty classroom Wednesday morning, shortly before the first class. And last month, Mr. Cronin's dormitory room took a direct hit from a 105-mm shell. American officials at the university now have two bodyguards each, even on campus.
Dennis Hilgendorf volunteered to come to Lebanon more than 20 years ago. Unlike thousands of foreigners who have fled during various crises here, Dr. Hilgendorf actually increases his involvement during trouble through his privately funded ''Contact and Resource Center'' relief group.
Genevieve Maxwell, a grandmother of seven, set up her base in Beirut in 1953 to write books and conduct tours of the region. She has left only once since the first Marine-directed evacuation in 1958. ''I went kicking and screaming all the way,'' she said. ''I refuse to be evacuated again.''
As the sound of shelling echoed in the distance, she explained how she had often lost windows to various bombs or spates of fighting in her neighborhood.
''Oh, we get this all the time,'' she said of the noise, ''but they're not close enough yet (to seek shelter).'' She keeps a pair of binoculars on the terrace to monitor events.
Most Americans say they will not leave, either because they love Lebanon or because they feel they have an important job to do, despite the hair-raising tales they all have.
The Kielys also hope to stay. ''Our staff is heavily American,'' Dr. Kiely said. ''If we go, they will go. If the Americans go, then the school will close down. And we have several students from the Middle East and Africa. We can't abandon them.''
Mrs. Kiely went further: ''I think some Americans are staying because they'd like to play a constructive role in a situation where the US government played such a destructive role. There is still a lot of good Americans can do in Lebanon.''
Like thousands of Lebanese, many Americans in Lebanon now say they feel abandoned by the Reagan administration. That sentiment was accentuated by the latest Mideast tour of special envoy Donald Rumsfeld, who held talks in nine other countries - including Iraq, which has no formal relations with the US - before coming to Lebanon last Thursday.
The low profile of the US Embassy in Beirut, traditionally one of the most active in the region, has also triggered anxiety and criticism among American civilians.
''I don't feel the US Embassy is doing anything,'' said Dr. Kiely after calling for guidance for his American staffers and foreign students and being advised only to stay indoors and vary paths of travel if he had to go out. A US Embassy spokesman conceded that there is no extra effort on behalf of non-embassy Americans beyond what is normally done.
The embassy, divided between two buildings since a bomb attack killed 64 people last April, is surrounded by fewer than 100 marines. The majority of embassy personnel who remained after the February evacuation now live behind the high fence of the compound in west Beirut. It is difficult for Americans to gain entrance without an appointment - in a country where the telephones are often out of order.
Ambassador Reginald Bartholomew, who lives in a tightly guarded residence in east Beirut, is ferried in by military helicopter. On land he travels in a convoy of bulletproof cars. Several Americans with years of experience in the region have compared the atmosphere at the facility to the pre-hostage era in Iran.
Both Lebanese and Americans have commented on the sudden switch, in less than one month, from a sense that the US seemed in charge of Lebanon's future - they ran this show, one said - to a feeling that US diplomats have little firsthand knowledge of what is happening on the ground around them.
Perhaps surprisingly, the majority of Americans in the capital live in the Muslim-dominated western sector rather than Christian-controlled east Beirut, where there have been no recent attacks on US citizens. Indeed, last week the Christian ''Lebanese Forces'' militia appealed to embassies and foreigners to move to their side, guaranteeing their safety. The offer has so far not been accepted.
Many US citizens who have decided to stick it out lay only partial blame on extremist local militias for the kidnappings and killings of Americans. They attribute a large part of the blame for the anti-Americanism squarely on the failure of US policy in Lebanon.
An American who has headed a prominent educational institution in Beirut since 1969, but refused to be identified for security reasons, said:
''There is no (US) policy. It's a cacophony. There's no direction. The whole business of bringing in the Sixth Fleet and the New Jersey (battleship) and making big noises about protecting the Lebanese government amounted in the end to nothing. We accomplished nothing at great cost. Those of us (Americans) left behind are paying part of the price.''