Answer
The Arya Samaj, a reformist Hindu movement founded in the 19th century, greatly influenced Lala Lajpat Rai's ideology and political activism. The Samaj advocated for social and religious reforms, emphasizing monotheism, rejecting idol worship, and promoting the study of the Vedas. Rai embraced these principles and became an active member of the Arya Samaj, incorporating its ideals into his political vision for India's independence and social progress.