Do you think I have come to bring peace on earth? No, I tell you, but rather division!52 For from now on there will be five in one household divided, three against two and two against three.53 They will be divided, father against son and son against father, mother against daughter and daughter against mother, mother-in-law against her daughter-in-law and daughter-in-law against mother-in-law.
Jesus brought division because some would believe in him and some would not. People feel very strongly about religious beliefs, so it is easy to see that severe tensions would happen in families and societies. History witnesses to the fact that this did happen. There are some references to this division in Scripture. For example:
John 9:16 Some of the Pharisees said, “This man is not from God, for he does not keep the Sabbath.” But others said, “How can a man who is a sinner do such signs?” And there was a division among them.
Acts 14:2 & 4 But the unbelieving Jews stirred up the Gentiles and poisoned their minds against the brothers. … (4) But the people of the city were divided; some sided with the Jews and some with the apostles.
We see in Matthew 10:36 that a person’s enemies would be those of his own household. And in the next verse, Jesus gives the warning that we must give our allegiance to him rather than to our family.
Matthew 10:34-38 “Do not think that I have come to bring peace to the earth. I have not come to bring peace, but a sword. (35) For I have come to set a man against his father, and a daughter against her mother, and a daughter-in-law against her mother-in-law. (36) And a person’s enemies will be those of his own household. (37) Whoever loves father or mother more than me is not worthy of me, and whoever loves son or daughter more than me is not worthy of me. (38) And whoever does not take his cross and follow me is not worthy of me.
Jesus also experienced division in his family. See Mark 3:31-35 & John 7:3-8.
I think Luke 12:52 is just giving an example of how division may occur. I don’t know of any particular significance of 3 versus 2 and 2 versus 3 in a family of five. Perhaps there was a particular situation in Jesus life that he was thinking of when he said that. Perhaps in his own siblings there was this division.
Discipleship is not necessarily an easy thing. It is committing our life to Jesus. It was not easy for Jesus either. We see in Luke 12:49-50, the great distress Jesus himself had to face, knowing he had to go through crucifixion.