He was speaking during a ceremony to commemorate James Connolly and the Irish Citizen Army.
President Higgins laid a wreath by the statue of James Connolly – remembering all those who died in the Easter Rising.
However he says that the republic of which the rebels dreamt has yet to be realised.
At the ceremony earlier the Starry Plough rebel flag was raised on the site it was first flown over Liberty Hall 100 years ago.
It was there that James Connolly gave his last address before the Easter Rising, stating boldly that the cause of Labour is the cause of Ireland.
In an address SIPTU President Jack O'Connor said that Connolly and the Irish Citizen Army didn't put the country first, but put people first.
President Higgins urged people to take up the cause of the Irish Citizen Army – saying there were too many people in poverty, without access to housing, childcare or healthcare.
It brought to a conclusion the commemorations of the centenary this Easter; however events will continue to mark 1916 for the rest of the year.
