Sayyidina Ibn Abbas (RA) explained the words of Allah, the Mighty, the Glorious:
"Whatsoever palm-trees you cut down, or left standing upon their roots, it was by Allah's leave, in order that He might abase the transgressors." (59: 5)
He said 'al-linah' is a palm-tree while 'abase to the transgressors is that the Mulims brought them (the Jews) from their forts. When they (the Muslims) were commanded to cut down their trees, they thought that they had cut off some and spared some, so they asked Allah's Messenger (SAW) about it : Will we be rewarded for the trees that we have cut down and punished for those that we have spared?" So, Allah revealed:
"Whatsoever palm-trees you cut down, or left standing upon their roots, it was by Allah's leave, in order that He might abase the transgressors." (59: 5)
--------------------------------------------------------------------------------