Luqman - 31:13

وَإِذْ قَالَ لُقْمَانُ لِابْنِهِ وَهُوَ يَعِظُهُ يَا بُنَيَّ لَا تُشْرِكْ بِاللَّهِ إِنَّ الشِّرْكَ لَظُلْمٌ عَظِيمٌ
[31:13]
And when Luqman said to his son while he admonished him: O my son! do not associate aught with Allah; most surely polytheism is a grievous iniquity--
Behold, Luqman said to his son by way of instruction: "O my son! join not in worship (others) with Allah: for false worship is indeed the highest wrong-doing."
And (remember) when Luqman said unto his son, when he was exhorting him: O my dear son! Ascribe no partners unto Allah. Lo! to ascribe partners (unto Him) is a tremendous wrong -