go to war
take arms
take up arms

There, however, the people took up arms at his approach.

The only thing we have to do is take up arms!

At other times, he has called on black people to take up arms against the police.

Some said they were prepared to return home and take up arms, if necessary.

At other times, officials said, he spoke of 10,000 people who would take up arms.

If I try to lead you away right now, these soldiers will take up arms again to stop me.

Men not taking up arms were given four days to leave.

The men of the town took up arms and drove them away.

But she left the religious group and took up arms.

Instead of taking up arms, he made education his life.