The words introducing the Lord's prayer were translated by Cranmer, felicitously, as ' ...we are bold to say'. New ICEL with equal accuracy renders '...we dare to say'. But surely we should be 'happy' to say or 'cosy' to say or at least 'confident' to say? Old ICEL, indeed, prayed 'with confidence', and the equally corrupt Common Worship translation totally skives the question of how to render 'audemus'. Yet there is quite an ecumenical convergence here (if one ignore the Modernists and considers just the healthy consensus of the classical Roman and Byzantine Rites): the Byzantines ask God to make us worthy, with parrhesia and without condemnation, to dare (tolmain) to call upon the God of Heaven as Father.
Lying behind the modern squeamishness is a feeling that Christianity should be a religion of intimate warmth. Indeed, there is in the world at large a belief that all men are brothers and that accordingly God, if there is a God, is the indulgent unjudgmental Father of all men. So why should there be anything bold or daring about calling him Father? Rather than being dangerous, it should be next door to a platitude.
But this is not the religion of the New Testament. The Lord's habit of regarding God as his father, Abba, seems to have been distinctive and unusual. The fact that the word is Aramaic suggests that it goes back to the Incarnate Lord's infant linguistic habits. And permission is given to humankind to share this habit in as far and only as far as humans are incorporated into Christ by Baptism and thus en Christo, members of his Body, Sons only in the sense that they are in the One Son. Wayne Meekes (The First Urban Christians) attractively suggested that the Pauline converts actually cried Abba (Gal 4:6) as they emerged dripping from the regenerating, resurrecting, waters of baptism.
Only because we thus share by the theosis of filiation in Christ's Divine Sonship dare we, as the Byzantines happily put it, with parrhesia (standing on our two feet and looking him in the eye) call God Pater.