"The lepers were required to act as though doing what Jesus asked would make a difference, even though there was yet no tangible evidence that it would (they had at least to believe that it was worth a try; cf. the commands to act with the expectation of healing in 5:25; 6:10; 7:14; 8:54; and cf. further 7:7–10; John 4:50)." Nolland, J. (1998). Luke 9:21–18:34 (Vol. 35B, p. 846). Dallas: Word, Incorporated.