The BJP's prime ministerial candidate for 2014 also told the young voters in his audience what secularism means to him. "I define secularism as nation first, India first. Justice to all, appeasement to none. No votebank politics - a poor man is a poor man, where he prays is immaterial." (Read: Highlights of Mr Modi's address)
On Tuesday, Prime Minister Manmohan Singh had said secular forces must come together to "stop the onslaught of people like Narendra Modi." The Gujarat chief minister's rivals question his secular credentials and accuse him of not doing enough to prevent communal riots in his state in 2002, when hundreds of Muslims were killed under his watch.
Mr Modi's was the concluding address at an event where students from 200 colleges shared their ideas for change in India. He arrived at Delhi's Thyagraj stadium at about 11 in the morning and stayed through the day, as presentations were made and other political leaders spoke. (Watch)
His focus was on governance as he sold his Gujarat model, but politics was implicit, not least when Mr Modi made a subtle dig at dynastic politics in the Congress: "In my family, no one knew the p of Politics... I used to be sell tea on trains and today I stand here in front of you. So stop thinking where you come from. If you want to change the country, start walking and you will find a way."
The crowd cheered lustily as he delivered his punchlines. Mr Modi had prefaced, much to their delight, his address with the suggestion that he chat with them rather than give a heavy speech.
He also shared the stage with Telugu Desam Party chief Chandrababu Naidu, who had once shown much reservation to being seen on the same side as Mr Modi. There has been speculation that Mr Naidu, once a BJP ally, might be looking at an electoral partnership again.