I Believe (thing)

  I believe in the one God, maker of heaven and earth,
  of everything visible and invisible.

  And in the one Lord Jesus Christ, his only son, (...)

A whole litany of 'I believe' (credo in Latin) is a fixed part of the Roman Catholic mass. The users profess their belief in God, some of the dogmas of the Christian faith, the Holy Church, etcetera.

Personally I'm more inclined to the response given by John Lennon in his song, 'God'.