Palestinian PM Ismail Haniya has said the suspension of Western aid to the Palestinians will never defeat the new Hamas-led administration.
Ismail Haniya's administration was sworn in last month
Nor, Mr Haniya said, would it defeat the Palestinian people.
He said the West would not succeed in isolating the government because it had the full support of Palestinians.
Mr Haniya was addressing Friday prayers in Gaza before the start of a series of rallies aimed at demonstrating support for the Hamas-led administration.
Thousands of Palestinians in the West Bank and Gaza have demonstrated in of support their new government.
The European Union and the United States have cut off all economic support for the government because Hamas refuses to renounce violence and recognise Israel.
Mr Haniya delivered his defiant and passionate address to thousands of supporters gathered at the main mosque in the Jabaliya refugee camp, the BBC's Alan Johnston in Gaza says.
The Palestinian prime minister said there would be, as he put it, no surrender, no buckling to the demands of Israel and the West.
"We will eat salt, but we will not bow our heads for anybody other than God, because we are faithful to the rights of our people and our nation. We will not betray it," he said.
After his speech, Mr Haniya joined thousands of Hamas supporters who thronged the streets.
And he went with them as they gathered for a major rally in the centre of Gaza City.
Earlier, at another big demonstration in the south, another Hamas leader had warned that if the party's government was broken by its enemies, Hamas would go back on the offensive.
Younes al-Aftal, a Hamas MP, said there would be Hamas suicide bombings again in the heart of Israel.
This is the first time a prominent Hamas leader has talked in these terms since the formation of Hamas-led Palestinian cabinet was sworn in on 30 March.
Hamas has carried out nearly 60 suicide bombings in Israel since the start of the second intifada in 2000.
It is currently maintaining a ceasefire, but remains committed to the destruction of Israel.