Maximilian more or less lived a rather lavish life over the course of the days that followed his discussion with Faisal I bin al-Hussein bin Ali al-Hashemi, and when the man returned to him, the verdict was clear.
The Arab leaders beneath the control of the Ottoman Empire had agreed to wage war. And they agreed to do so in exchange for the terms Maximillian had presented to them.
In other words, in exchange for allowing the independence of the Islamic World following the defeat of the Allied Powers, and their right to rule their own lands without European influence, they would take up arms against the Allied Powers, primarily the Ottoman Empire and their allies fighting alongside them within their territory.