These chapters are on Jesus’s discourse about the destruction of Jerusalem and the temple (AD 70) and then the Second Coming, which has not happened yet, 2000 years later (and counting). Looking at the chapters side by side clarifies what he really taught.
Jesus teaches forgiveness, particularly when sins are inevitable. The disciples ask to have their faith increased. Jesus urges his disciples not to expect a loud thank you and thunderous applause for doing minimal work. He heals ten lepers. Jesus teaches on the Second Coming.