Tafsir of Az-Zukhruf 43:86

وﻻ يملك الذين يدعون من دونه

And those whom they invoke instead of Him have no power, means, the idols and false gods.

الشفاعة

of intercession, means, they are not able to intercede for them.

إﻻ من شهد بالحق وهم يعلمون

except for those who bear witness to the truth knowingly, and they know. This means, but the one who bears witness to the truth has knowledge and insight, so his intercession with Allah will avail, by His leave. The Idolators admit that Allah Alone is the Creator Allah exalted says,

ولين سٲلتهم من خلقهم ليقولن الله فٲنى يوفكون