"I love my country and I'm proud of how far we have progressed. And I know that by working together as one nation, our best days are still to come," he said in his blog.
Najib was reelected to a second term in office when his ruling Barisan national coalition won Sunday's general elections.
Najib promised that the Barisan Nasional Government would make efforts to ensure any form of extremism and racism would be tackled.
In the 13th general election last Sunday, Barisan retained power by securing a simple majority of 133 out of the 222 parliamentary seats.
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Najib also admitted the recent general election had been a long and hard-fought battle.
"There have been a lot of strong views and different ideas over the last few weeks. There has been passion and sometimes even anger."
Multi-ethnic Malaysia has 60 per cent Malays, 25 per cent ethnic Chinese and eight per cent ethnic Indians.
This elections saw ethnic Indians heavily backing the ruling coalition unlike last general elections when they backed the opposition.