BBC reported that it now has evidence that al-Qaeda in Yemen is fighting on the same front as the Saudi coalition.
The Saudi rulers launched a brutal war that killed tens of thousands of civilians in Yemen, has also created a foothold for al-Qaeda and ISIL in that country. For instance, when the Saudi coalition pushed the Yemeni army and their Houthi allies out of Aden, al-Qaeda and ISIL moved in and they are now in control of many neighborhoods of that city.
Despite the Saudi rhetoric that they are committed to fighting terrorism, the kingdom's military did not attack, in any significant way, al-Qaeda fighters in Yemen or anywhere else. That makes their offer to send troops to fight ISIL in Syria highly suspicious.
Saudi Arabian rulers are interested in staying in power, not fight terrorists who espouse Wahhabi-Salafism, which is deeply rooted in Saudi society.