Imam al-Jawad (a.s) said:
مَنْ عَمِلَ عَلى غَيْرِ عِلْم أَفْسَدَ أَكْثَرَ مِمّا يُصْلِحُ
One who acts without knowledge and information will more often be a corrupter rather than a reformer.1
Loss caused by ignorance is not merely limited to inability to make significant achievements in life. Those who act without knowledge also risk making dangerous mistakes leading to corruption and destruction.
One finds cases where an ignorant person intends to do good for his child, but he leads him to misfortune; intends to serve Islam, but disgraces religion; intends to create peace among people, but aggravates disputes and hypocrisy. He generally ends up doing more harm than good.