Mark 6:7

Jesus called the Twelve to Himself and then sent them out as His official representatives (cf. Mark 3:14). In Jesus’ culture, one sent was regarded exactly as the one who sent him. [Note: Lane, pp. 206-7.] Jesus was following Jewish custom and wisdom in sending the disciples out in pairs, which Mark alone mentioned (cf. Deuteronomy 17:6; Deuteronomy 19:15; Ecclesiastes 4:9-12). This was primarily to validate the truthfulness of their message by providing two witnesses (cf. Numbers 35:30; Deuteronomy 17:6). The Twelve were to preach the kingdom of God (Luke 9:2) and to perform miracles to authenticate their message for their Jewish audiences (Matthew 10:1; Luke 9:1-2). Mark just mentioned casting out demons as the most powerful demonstration of Jesus’ power at work through them. This was a mission that would prepare the Twelve for larger responsibility in Jesus’ service later.

"Jesus authorized the disciples to be his delegates with respect to both word and power. Their message and deeds were to be an extension of his own." [Note: Ibid., p. 206.]