Is this a dagger which I see before me,
The handle toward my hand?

Macbeth’s dagger was not in a war, unless it was a battle in his mind.

Get into your stride means get into a rhythm and can be applied to settling down to work.

Steal a march is a way of getting ahead of the enemy perhaps by marching overnight or making a very early start.  It is used in civilian life about getting ahead of rivals.

Out of step
is not conforming.  An army marches in step.

About turn!
Turn round to face the way you have just come!

A passing out parade
is held at the end of a training course for recruits.  Passing out can also mean fainting and it is not unknown for soldiers in uniform to pass out on parade in hot weather!

Company dismissed!
This is the military equivalent of  “You may go now!”

In the thick of it
comes from a battlefield.  Where there are most people fighting they are not thin on the ground but rather in the thick of it.

In the front line
is where two armies meet.

Stand your ground
is advice to a defender.  As the enemy approaches the defenders must not be driven back.  It also applies to sticking to a point of view in an argument.

Attack is the best form of defence.
This saying can apply to speech as well as war.

Spearhead a mission
is a phrase which means lead.  The head of the spear goes first, when it is thrown.

To lie in wait
could be the preparation for an ambush.

Take by storm
means have success.  In warfare troops might attack a city by storming it.

Gird up your loins
Smite them hip and thigh
are phrases found in the Bible.

In 1 Kings 18:46 in the King James (or Authorised) Version “Elijah girded up his loins“.  The NIV translates this as “tucking his cloak into his belt”.

Judges 15:8 has Samson “smote them hip and thigh” or (NIV) “attacked them viciously and slaughtered many of them”.