Surveys of religious activity and interest indicate that the last two decades of the 20th century could be a time of ''profound religious renewal'' in American society, says pollster George Gallup Jr.
At the same time, he cautions, his polls also show ''worrisome trends'' that make renewal by no means certain.
Mr. Gallup reported at a recent meeting of the American Bible Society significant increases over the past few years in the percentage of American adults involved in some form of religious education.
There also was an increase in the number sharing their faith through some form of evangelization.
The number of teen-agers participating in Bible study increased from 27 percent in 1978 to 41 percent in a recent poll, he says.
Despite such activity and the high regard for the Bible expressed by even larger percentages of Americans, actual knowledge of the biblical content remains extremely limited, Mr. Gallup says.
Relatively few people, his surveys find, know what Jesus told Nicodemus (''Ye must be born again'') or can name as many as five of the Ten Commandments. ''Americans venerate the Bible but don't read it a lot,'' he says.
Gallup also reported finding high levels of ''credulity'' mixed with genuine religious interest.
Belief in astrology is as high among churchgoers as among nonchurchgoers, he says.
But he adds that ''the vast majority'' of Americans want their children to have religious education, wish their own beliefs were stronger, and want religion to play a stronger role in society.