"For on the eve of that sudden assault a dream came to my brother in a troubled sleep and afterwards a like dream came oft to him again, and once to me. ... Therefore my brother, seeing how desperate was our need, was eager to heed the dream and seek for Imladris...." Boromir said.
'Then it is as i feared,' Elrond thought, 'the one who was called has remained. What then shall become of this quest without Faramir? Or perhaps he has a purpose more noble than this.... Though the Valar must have been desperate to call Boromir as well.'