It’s funny you pick this line because I was just thinking about it recently. Many of Christ’s words are not meant to be easy to understand, in fact they often perplexed his own disciples.

My own take on this passage is that following Christ’s message, truly following it (such as love your enemies for example) will not be something everyone can do. When some in a family can truly love someone society tells them to hate (i.e. commonly discriminated group of people) and the rest can’t, this will sow division.

Sometimes we have to stand up to our own families in order to truly love others. It’s much easier to just keep things “peaceful” in the family, at a cost of your slowly deteriorating soul/spirit.

That’s my take.