In seeking the restraining order yesterday, the Justice Department called into the proceedings a law which makes it a criminal offense for any person to "have unauthorized possession" of classified documents or to communicate, deliver or transmit such documents "to any person not entitled to receive them."

In addition, Jerry Friedham, a Defense Department spokesman, said Monday another law-making it a crime to publish information of a classified nature-may be involved.

The implication is that Times publisher Arthur Ochs Sulzberger and 21 other reporters, editors and officers of the Times named in the Justice Department suit are subject to penalties of ten years in prison or fines of up to $10,000 or both under either law.

"There is absolutely no way I can imagine these laws being applied in this case," one Law professor gasped. "The only possible application is one of aiding and abetting espionage, and that is simply absurd."

Attorney General John N. Mitchell told the Times Monday in a telegram that publication of the Pentagon material violates espionage laws.

Assistant U. S. Attorney Michael D. Hess, who filed the suit in New York, said the three installments of the series-published on Sunday, Monday and yesterday-have "seriously interfered with the conduct of our foreign relations."

One Law professor dismissed that contention as "silly."

Meanwhile, newspapers across the country have leaped to the Times's defense and Senate Majority Leader Mike Mansfield said yesterday the Senate will hold hearings on the Pentagon's study "regardless of what the decision of the court is."

One publisher of a major daily newspaper said last night that the Justice Department's suit "can only lead to the ultimate embarrassment of the government."

This view was repeated by professors at the Law School, who cited increasing judicial hostility to the war over the past year as another major factor working against the government.

Still, the professors were hesitant to anticipate Gurfein's decision. As one sympathetic to the Times and Judge Gurfein said, "When you get right down to it, if I were in his position, I would throw up my hands and go home."