As anybody who drives the 14th Street bridge and Southwest Freeway knows by now, Congress is back in town, government workers have used up accumulated leave, and the slackened holiday-period traffic is back to (ugh!) normal.

As the lawmakers returned, the first order of business was the chaplains' prayers in both chambers. They didn't pray for Messrs. Gramm or Rudman or O'Neill or other members individually, although the Rev. Richard C. Halverson, chaplain of the Senate, did include thanks "for the recovery of Sen. Lawton Chiles D-Fla. and his renewal of strength" after heart bypass surgery.

Here, excerpted, is what the two chaplains prayed for at the outset of what is sure to be a tumultuous second session of the 99th Congress:

"You know, Lord, that Congress confronts a monumental task these next eight months which will test the wisest and best of human capacity," invoked Halverson in the Senate. "Infuse Your servants, the senators, with the will to meet the challenge head-on, to give leadership which they alone can give, the wisdom to process complicated and conflicting data and the courage to do whatever must be done at whatever cost to themselves.

"Enable the senators to make these next eight months a period of unprecedented and significant legislation which will prove false the prognostication of the cynics and the pessimism of self-appointed detractors.

"In the name of the Lord for Whom nothing is impossible. Amen."

The Rev. James David Ford, chaplain of the House, was perhaps less pointed. After voicing thanks for peace and wisdom and invoking the need for vision, he prayed: "May we see in our tasks opportunities for service not only to those under our special care, but to use all our talents, our minds, our hearts, our treasure, to promote justice and peace and so do Your will on Earth as it is in Heaven. Amen."

When President Reagan used amplifiers to address the Right-to-Life marchers on the Ellipse yesterday, he followed a precedent set in 1921 by a previous occupant of the White House, Warren G. Harding. Harding was the first to speak to the crowds in that way on his inauguration day, and he did so a second time in 1923 for the dedication of the Zero Milestone, the granite block on the Ellipse that was intended to measure the distance by road from Washington to any point in the nation.