John Trapp on Isaiah 30:6

Ver. 6. The burden] i. e. the gifts and preſents wherewith the Hebrews beaſts were laden to carry ſouthward, to hire help from Egypt. A mans gift maketh room for him, Prov. 18.10. Philip was wont to ſay, that he doubted not of taking any town or tower, if he could but thruſt into it an aſs laden with Gold. But theſe Jewiſh Ambaſſadors loſt both their labour and their treaſures, carried upon the ſhoulders of many young Aſſes, and upon the bunches of Camels to a very great quantity. See what a preſent was ſent to a poor Prophet, even of every good thing of Damaſcus forty Camels burden, 2 King. 8.9. and gueſs by that what a deal of wealth went now to Egypt to procure help.

Into the land of trouble and anguiſh] that great and terrible wilderneſs of Arabia, wherein were fiery ſerpents and ſcorpions, Deut. 8.15. and other fell-creatures not a few: Thorough that waſte howling deſert, Deut. 32.10. that lay between Judea and Aegypt, travelled theſe beaſts with their burdens; but all was labour in vain, and coſt caſt away, becauſe God was not of the counſel.