Luke wrote this Gospel so ""that you Theophilus] may have certainty concerning the things you have been taught i.e., catechesis]"" (1:4). It proceeds with a barrage of questions. The first comes from Zechariah: ""How shall I know?"" (1:18). This is a question of knowledge. The angel Gabriel answers that we shall know by the word of God (1:19). The second comes from Mary: ""How will this be?"" (1:34). This is a question of agency, of how the Son...