Modi said he considered it "a signal from God" that he got the chance to address an ex-servicemen's rally immediately after being named the BJP's prime ministerial candidate.
He revealed that he wanted to study in a Sainik School but could not fulfil his dream due to his family's financial status.
He said he procured the prospectus of a Sainik School by saving and sending Rs.2 when he was a class 4 student.
"At that time, service of nation meant going to Army," he said.
However, Modi his father could not afford to pay the money to sit in the entrance test for Sainik School and his dream of joining it died.
Modi said he was a class 6 student during the 1962 war with China and went to Mehsana railway station to serve soldiers going to the border.
"I went to Mehsana without telling my father and served them tea, breakfast and pressed their feet for days," Modi said, who greeted the ex-servicemen by folding his hands.
Some of the posters outside the venue of Modi's rally here had a interesting take on who should be Haryana chief minister after Modi becomes prime minister.
Apparently put up by Haryana Janhit Congress (BL), the posters said that party MP Kuldeep Bishnoi should be the chief minister.
Bishnoi, whose party has an alliance with BJP in Haryana, was present at the Modi's ex-servicemen rally.
Haryana will go for assembly polls after the Lok Sabha elections next year.
Cutouts of Narendra Modi greeted people near the venue of the ex-servicemen's rally at Rewari with the organisers having pulled out all stops to make the first outing of the BJP's newly crowned prime ministerial candidate a success.
There were three hoardings behind the state each with a huge Modi photograph.Modi shared the dais with ex-servicemen who had retired from the services on senior ranks, including former army chief, Gen. (retd.) V.K. Singh. He began by asking the enthusiastic gathering to repeat "Bharat mata ki jai" after him.
Modi mentions Vajpayee thrice, Advani once
While former prime minister Atal Bihari Vajpayee found mention in Modi's speech at least thrice, party patriarch L.K. Advani - who has not welcomed Modi's elevation - was mentioned only once.
One of the three hoardings on the dais had a big picture of Modi along with party president Rajnath Singh and Vajpayee, but there was only a small photo of Advani at the top of the hoarding along with party leaders Sushma Swaraj and Arun Jaitley.
Rewari was chosen as the venue of the rally as the town and adjoining areas have a sizeable population of ex-servicemen.
Locals said that families have tradition of sending young men to the Army.
Former army chief Gen V.K. Singh, in his speech, recalled the bravery of people of the area and that 114 soldiers from the area had laid down their lives in the battle of Rezang La during the 1962 war with China.
Modi stressed on the connection between Haryana and Gujarat, saying he knew villages of Haryana as he had worked for the BJP in the state.
Modi said the Arya Samaj had a wide influence in Haryana and he was given respect by people merely because he belonged to Gujarat to which Arya Samaj founder Maharishi Dayanand Saraswati also belonged.
He also recalled that the two states had sites associated with Lord Krishna.
Modi made a veiled attack on Janata Dal-United over remarks of Bihar's Panchayati Raj Minister Bhim Singh that people join army and police to get martyred. The remarks came days after five Indian soldiers were killed near the Line of Control in August.
"It is the limit of shamelessness when a public representative says that people join the army to die. No leader, no political party would have made a more humiliating remark," Modi said.
Bhim Singh was pulled up by his party leadership over the remark.
JD-U leader and Bihar Chief Minister Nitish Kumar is a critic of Modi and had parted ways with BJP after Modi's elevation as chief of BJP's campaign committee for 2014 Lok Sabha polls.