BOSTON -- “More than Israel has kept the Sabbath, the Sabbath has kept Israel,” Cardinal Seán P. O’Malley said he once read in a synagogue prayer book.

“What a great truth that is,” he said. “More than we have kept the Sunday Mass obligation, it has kept us as a people focused on God.”

Cardinal O’Malley spoke about “Prayer and Discipleship” in a packed room at the Christ Speaks in the City lecture series Dec. 13.

The lunchtime lectures are held at the Old State House in downtown Boston in an effort to reach out to young adults who work in the city. Sponsored by the Archdiocese of Boston’s Vocations Office, they began in the fall of 2006, and each fall and spring feature four speakers. This was the cardinal’s third time speaking as part of the series.

Cardinal O’Malley continued by saying that the Mass is the highpoint of the spiritual life of Catholics. The liturgy contains different kinds of prayer, including adoration, contrition, praise, thanksgiving and petition, he said.

But before people can appreciate the Mass, they must develop an interior life of prayer and bring that to the celebration of the liturgy, he said.

“In the Sermon on the Mount, Jesus tells us to go to our chamber, shut the door and pray to our Father in secret because it’s not enough if we just participate in the public act of worship,” he said.

Both personal and communal prayer are necessary in order to do the will of God, the cardinal said.

“Without prayer we cannot find the way to the Lord, we cannot understand the truth, we cannot crucify the flesh and its passions and lust, one’s heart cannot be enlightened with the light of Christ, nor can it be united with the Lord,” he said. “None of these things can be effected unless they are preceded by constant prayer.”

Cardinal O’Malley continued, saying that people often mistakenly believe that prayer must be spontaneous or poetic.

“Jesus, in the Gospel, so often prays prayers that he learned as a child from Mary and Joseph,” he said, adding “With a dying person, when you’re praying the Hail Mary, ‘pray for us now and at the hour of our death,’ those words take on such meaning.”

Jesus also gave a model of prayer when he taught the disciples to pray the Our Father. Within that prayer is the heart of all Christian prayer: “Thy kingdom come. Thy will be done.” Disciples of the Lord must understand that nothing can be better than God’s will, he said.

Disciples must pray for the Lord’s will, as did Mary when she prayed at the annunciation, “Be it done unto me according to thy word” and Jesus who prayed in the Garden of Gethsemani, “If it is possible, let this cup pass from me. Yet, not as I will, but as you will,” he said.

“We are called to trust in God’s love for us,” the cardinal said.

Followers of Christ must also trust in the Lord’s loving providence, praying, “Give us this day our daily bread,” and waiting for tomorrow to ask for tomorrow’s bread, he added.

Cardinal O’Malley related a modern parable for the spiritual life, taken from the movie “Contact.” In that film, scientists are constantly sending out messages to outer space, trying to communicate with any intelligent life. They receive a message back, inviting them to travel into space and meet those aliens.

“We have to be a people that is listening for God, his word in our life, and (is) ready to build that bridge, that spaceship, that will carry us to God. That is the life of prayer.”

Caitlyn O’Keefe, parishioner at St. Francis of Assisi Parish in Weymouth, works in downtown Boston and said the Christ Speaks lectures give her a sense of inspiration during her busy workweek.

“In the workplace religion and spirituality are sort of taboo,” she said. “This is something I’ve been looking forward to all week. It breaks up my day. It’s another facet to who I am.”