"The one God, the Trinity of love, allows the variety of witnesses to flourish -- all are equal in dignity, but also unique in the beauty that the Spirit has willed to be expressed in each of those whom God's mercy has made his children," the pope said March 17 during his weekly general audience.

During the audience livestreamed from the library of the Apostolic Palace, Pope Francis concluded his series of talks about prayer by looking at prayer as a relationship with the Holy Trinity, in particular with the Holy Spirit.

"The first gift of every Christian existence is the Holy Spirit," he said. It is the key, essential gift because without the Holy Spirit, "there is no relationship with Christ and with the Father."

The Spirit opens the human heart to Christ's presence "and draws it into that 'vortex' of love that is the very heart of God," he said.

The Holy Spirit "dwells in us; it is he who transforms us deeply and makes us experience the moving joy of being loved by God as his true children," the pope said.

The Spirit writes the story of the church and of the world, he said, and "we are open pages, available to receive his handwriting."

"In each of us, the Spirit composes original works because there is never one Christian who is completely identical to another," creating a vast and flourishing "field of holiness."

The church invites the faithful to call upon the Holy Spirit every day, to make Christ present so he can guide and transform his disciples, he added.

Calling on the Spirit for support and inspiration is important, especially when one has not prayed in a long time, has lost the desire to pray or recites prayers "like a parrot," with no depth of feeling or faith, he said.

"This is the moment to say to the Spirit, 'Come. Come, Holy Spirit and warm my heart. Come, teach me to pray, teach me to look to the Father, the son, teach me the way the path of faith goes, teach me to love, and above all, teach me to have an attitude of hope.'"

"If Christ were only far away in time, we would be alone and lost in the world," Pope Francis said, but with the Spirit, "the possibility of encountering Christ is open to Christians of every time and place."

Christians must "keep alive this flame" of the Holy Spirit, of God's love, in their heart, the pope said, the same way the lamp next to the tabernacle stays lit "even when the church empties and darkness falls, even when the church is closed."

"No one sees it, yet it burns before the Lord," he said. "That's how the Spirit is in our heart, always present like that lamp."