John Gill Commentary Numbers 11:23

"And Jehovah said unto Moses, Is Jehovah`s hand waxed short? now shalt thou see whether my word shall come to pass unto thee or not." — Numbers 11:23 (ASV)

And the Lord said to Moses
In answer to his objection, without upbraiding him with his sin of unbelief:

Is the Lord's hand become short ?
Or his power diminished since the creation, when he formed all things out of nothing, and what is it then he is not able to do?

Or since he wrought the wonders in Egypt, divided the Red sea, rained down manna from heaven, and smote the rock at Horeb, from which waters flowed sufficient for all this people, and their flocks and herds; and he that did all this could give them flesh that would suffice them a whole month, see (Isaiah 59:1) ;

You shall see now whether my words shall come to pass to you or
no ;
Whether I am able to make good my promise; a short time will decide it, it shall be seen presently whether I am and will do what I have said.