As per ancient Puranas, devotion can evoke divine power in any innate object. Idol worship is a form of expression of love, divinity, and faith in your God. These idols have been created by master craftsmen who know how to bring the divine grace alive into metals like brass and bronze.
So, it is important to understand that the Hindus do not worship idols yet worship them as the physical representation of divine power. It helps people to focus and direct their prayer and meditate well.