The Quran

ما تَعبُدونَ مِن دونِهِ إِلّا أَسماءً سَمَّيتُموها أَنتُم وَآباؤُكُم ما أَنزَلَ اللَّهُ بِها مِن سُلطانٍ ۚ إِنِ الحُكمُ إِلّا لِلَّهِ ۚ أَمَرَ أَلّا تَعبُدوا إِلّا إِيّاهُ ۚ ذٰلِكَ الدّينُ القَيِّمُ وَلٰكِنَّ أَكثَرَ النّاسِ لا يَعلَمونَ

Muhammad Asad

"All that you worship instead of God is nothing but [empty] names which you have invented¹ - you and your forefathers - [and] for which God has bestowed no warrant from on high. Judgment [as to what is right and what is wrong] rests with God alone - [and] He has ordained that you should worship nought but Him: this is the [one] ever-true faith; but most people know it not.²

Lit., "names which you have named" - i.e., "figments of your own imagination".
Cf. the last sentence of 30:30.