All souls are alike, neither born nor dead: Vardhamana Mahavira

Vardhamana Mahavira, the 24th and last Tirthankara of Jainism, shared profound insights on the concept of immortality and the nature of the soul. While he didn’t specifically focus on immortality in the traditional sense, his teachings revolved around the eternal nature of the soul and its liberation from the cycle of birth and death (samsara). Here are some quotes attributed to Mahavira that touch upon these ideas:
"All souls are alike, neither born nor dead, eternal and everlasting."
"The soul comes alone and goes alone, no one companies it and no one becomes its mate."

"A living body is not merely an integration of limbs and flesh but it is the abode of the soul which potentially has perfect perception (Anant-darshana), perfect knowledge (Anant-jnana), perfect power (Anant-virya), and perfect bliss (Anant-sukha)."
"The soul of every living being is potentially divine, and it is its destiny to manifest that divinity."
"The soul is a substance, indestructible, eternal, and indivisible; it can only be described, not defined."