Jesus addressed these words to His disciples primarily (cf. vv. 41-42).
12:49-50 In view of the context Jesus' reference to fire must be as a symbol of judgment primarily rather than purification, its other common signification in Scripture. He had just spoken of judging unfaithful disciples (vv. 45-48). Now He explained that one of the purposes of His incarnation was to bring judgment to the earth (cf. 3:16). Perhaps Jesus wished this aspect of His ministry was taking place already because it would result in the purification of His people and would usher in the kingdom. However before Jesus' judging ministry could begin, Jesus Himself would have to undergo judgment, which He pictured as baptism. It would overwhelm Him but only temporarily. He would rise from it as a person experiencing water baptism rises out of the water. The prospect of His baptism (i.e., the Cross) distressed Him because it involved bearing God's wrath for the sins of humankind.
12:51-53 Evidently Jesus meant that He did not just come to bring peace on earth but also division. Jesus' earthly ministry began this division. From the time Jesus appeared preaching publicly, even households, the tightest social units, began to experience division. The difference of opinion that divided people was their beliefs about Jesus' person and work. This situation would continue. No physical relationship would escape the possibility of this division (cf. Mic. 7:6). This situation posed a crisis for the future. Historically division in the Tribulation will precede peace in the Millennium.
"Since detachment from family is another repeated theme in Jesus' teaching about discipleship (see 9:57-62; 11:27-28; 14:26; 18:28-30), the inclusion of 12:51-53 helps to make Luke 12 a comprehensive discourse on central themes of Jesus' teaching to his disciples."317
