Just singing and sinning in the rain. Lucille Banks Miller, public relations director of religious radio station WYCB, the Rev. Imagene Stewart, pastor of the Church of The What's Happening Now, Calvin Rolark, publisher of the Washington Informer newspaper, and a host of other city preachers and self-styled missionary evangelists descended yesterday into the junkies' den on what some folks here call the meanest corner in the city, Seventh and T streets, NW.

They prayed, "Thank You, Jesus" and "Praise the Lord." They showered passersby with testimonies and Bible verses and pamphlets like the cool rain that fell around them. And when the spirit built up inside, "Well, Well," and "Amen, Amen," they marched in threes down Seventh Street past the cursing winos and the junkies, some grinning, some nodding, and all of them letting the singing aunts and grandmothers and sanctified sisters and brothers weave amid the drug traffic and the fists of dollars changing hand to hand.

A young man in a yellow Lacosts shirt smiled, said "Hallelujah!" and sang "I'm so glad Jesus lifted me." Another in a skipper's cap danced some lively steps in front of the marchers, but was careful not to spill a drop of liquor from his plastic foam cup.

"We are here because we are concerned," shouted Sister Miller. "Some mother's son is down here. It could have been my son. It could have been me."