LAWRENCE - One chair at the altar was left empty during the 6 o'clock Mass last night at St. Mary of the Assumption Church.

The seat facing the crucifix behind the altar was reserved for Army Spec. Alex Jimenez, 25, missing since May 12 when his unit was ambushed by insurgents linked to al-Qaida.

His father, Ramon "Andy" Jimenez, sat just a few feet away, his gaze shifting from the chair to the packed congregation of family members, friends and total strangers who gathered to pray for Alex's safe return home.

"This gives me a lot of hope," said Jimenez, who drove alone from New York for the service.

He lives on Albion Street in Lawrence but had been in New York since learning of his son's disappearance.

Jimenez said he will remain in the city until he hears news of his son, then will likely return to New York, where Alex's mother and other family members live.

"It's appropriate for us to gather as a community of faith on this day," said the Rev. Jorge Reyes, pastor at St. Mary, during the homily marking the feast of Corpus Christi.

Reyes pointed to the chair and told the congregation of its significance

"We are here to support Alex' family, who are waiting for his return," he said. "Let us pray that Alex may come back soon so that chair is no longer empty."

Before the Mass ended, Reyes read a letter from Cardinal Sean O'Malley, offering his prayers for the safe return of Jimenez.

"It is good to know that the parish and the wider community are seeking strength and support in the celebration of the Eucharist and the public witness of their love for Alex and their prayers for him," the cardinal wrote. "Alex provides us an example of selfless love and dedication, giving of himself for others through the service of his country

The letter was faxed at 3:16 p.m. yesterday. Coincidentally, the New Testament passage John 3:16 reads, "For God so loved the world, that He gave His only begotten Son that whoever believes in Him shall not perish."

During the Mass, Andy Jimenez sat with hands folded, looking out to the congregation or fixing his eyes on the marble floor. Jimenez did not tap his feet as the rhythm of drums, guitar and keyboard played hymns.

He kept his composure until Reyes pointed to the chair and mentioned Alex's name. Then he began to cry.

"I kept thinking of how he was not sitting there," the older Jimenez said later.

On the altar was a poster of Alex posing in front of an American flag and the words in English and Spanish, "We are with You!" and "Estamos Contigo."

Alex Jimenez' cousin Jose Peralta, who lived with him on Water Street, was overcome when he saw the photo and left the church soon after.

Andy Jimenez took comfort from the photo.

"When I saw the photo, I felt like Alex was with me," said Jimenez, who wore light-gray pants with a white shirt and a yellow ribbon with red, white and blue stars

Jim Sereigo-Wareing of Merrimack Valley Care made 250 of the ribbons to pass out at the Mass and ran out early as more than 1,000 filed the church.

The Mass was full of symbolism.

When the bread and wine were brought to the altar, there was also a single white rose in a vase of water, a lemon cut in two and salt. The rose was for those who have died in the war; the water signifying their baptism. The lemon symbolized the bitterness suffered by the families of those missing in action, and the salt the tears shed by families waiting for their loved ones to return.

When it came time to exchange a gesture of peace, Andy Jimenez was mobbed by family members and friends.

Ana Estrella, Alex's cousin, hugged him tightly as both wept.

Many others were in tears after the Mass as they prayed during a candlelight vigil that was to continue until midnight.

Josefina Tejada of Lawrence, whose nephew, Josue Valerio, is in Iraq, planned to stay.

"I'm always praying for peace," Tejada said. "Having a family member serving in the war is too painful because you're always thinking of what can happen to them. That's why we have to remain faithful to get through this."

Also attending the service for the Jimenez family was Ann Sheerin of Salem, N.H.

"I don't know them, I'm just here to support them," Sheerin said. "I hope it's a bit of healing for them. I think it's important for everyone to come together because he's fighting for our country."

After the Mass, Andy Jimenez was asked if he believes his son is still alive.

He put his hands over his heart and said, "I feel it. I know it. I believe he is alive.

"When I talked to Alex, we never talked about the war," he said. "All I asked him was if he was OK. All I want to hear is, 'Papi, I am OK.'"

Family members and others have kept up hope that Jimenez and Pvt. Byron Fouty, 19, of Waterford, Mich., who was abducted with him, will be found alive. Their fears were raised when terrorists last week claimed the two soldiers had been killed but offered no proof. The body of a third abducted soldier, Pfc. Joseph Anzack Jr. of Torrance, Calif., was found in the Euphrates River on May 23.

Niviades and Melaida Estrella of Lawrence are not Catholics, but they attended the Mass and stayed for part of the vigil as a sign of support for Andy Jimenez, whom they have known for 13 years.

The couple was dressed in black and white.

"This is not a sign of mourning," said Niviades, who along with his wife is a member of the Seventh Day Adventist Church in Lawrence. "This is to tell him we love him."

"We are here for a friend who is suffering. We have hope that he is alive," Niviades said.

After leading the congregation in high-tempo music, choir members and musicians held hands, bowed their heads and prayed in silence during the vigil.

In between prayers and hymns, there were speakers who included Leonardo Jorge of Methuen, who serves in the Navy.

He said his faith and the support of his fellow soldiers gave him strength while he was in Iraq.

"Pray for those who are looking for Alex because they will never give up," Jorge said. "I know what it is like to lose a brother. I know what is like to go two weeks without bathing and shaving, getting little sleep and going hungry. But if given the option, they would prefer to keep looking for their brother. If I had chance, I, too, would be looking for him."

Another speaker, Edward V. Mitchell, director of the North Andover veterans services and a 20-year veteran of the Navy, said he can understand with the anguish and pain of the family.

"Relying on your faith, family and friends is all that you have," he said. "I'd rather do another 20 years (of service) than go through what the Jimenez family is going through. I'd rather do another 20 years rather than endure the separation, anxiety and stress. Relying on your faith, family and friends is all that you have."