LibriVox publishes free public domain audiobooks, mostly pre-1923 out-of-copyright works, which are recorded by volunteers. The collection includes two classic historical Jesus works (which you might want to play on your phone as you are out jogging):
David Friedrich Strauss, Life of Jesus Critically Examined, tr. George Eliot (German original, 1835; English tr. 1860)
Albert Schweitzer, The Quest of the Historical Jesus, tr. William Montgomery (German original, 1906; English tr. 1910).