What did Jesus mean by the 'beginning of travail' in relation to the Revelation horsemen?

The “beginning of travail” means the Revelation horsemen mark only the early labor pains of coming planetary events. Like a mother’s first contractions, these judgments are relatively mild and far apart, yet they initiate the delivery process that will intensify until the end, with special focus on Israel's tribulation.

Les explains that Jesus was pointing to all the events coming on the planet, beginning with the horsemen of Revelation. Those horsemen are just the beginning, comparable to a mother about to deliver: her birth pains are initially mild and far apart. As severe as these early events seem, they are mild compared to what comes at the end. So these things are only the beginning of travail, the start of the delivery process. Les also connects this to Jeremiah 30:7, the time of Jacob’s trouble, a tribulation unlike any other, whose vortex falls on the nation of Israel.

What events is Jesus referring to when He talks about the beginning of travail?

Jesus refers to the events coming on the planet, beginning with the horsemen of Revelation. They are the beginning of travail, comparable to a mother’s early birth pains—mild and far apart—before the far greater end. This period centers on Israel as the time of Jacob’s trouble.