In Jainism, Tirthankaras are perfected souls who have conquered all karmas and attained keval-jnana (omniscience). They are born on earth in each cosmic cycle to revive and teach the Dharma when it has declined.

However, after they attain moksha (liberation), they do not take birth again. So:

• Before moksha: Yes, Tirthankaras are born on earth (as human beings) to revive the path of right conduct.
• After moksha: No, they do not take birth again; they remain liberated in siddha-loka.

This view is consistent in both Digambara and Śvetāmbara traditions.