In a speech ahead of the march, Grand Chaplain Henry Williamson said: "Brothers and sisters, in a world of instability, a world of insecurity, a world of nuclear proliferation, of radical Islam, people look to the UK as a land of hope, a land of peace, of success and unity and an example if what they so desperately long for - unity not stupidity, unity not division, unity not separation, unity not them and us.
He added: "Let me remind you that when an enemy came against the city of Londonderry, God's people famously said there will be no surrender to this evil enemy.
"It was a cry we made in 1914, it was a cry we made in 1939, it is a cry British people make every time we face an enemy who seek to destroy who and what we are, and a cry that we make on behalf of the underdog.
"Well, a divisive and evil enemy has arisen against Scotland in the guise of false patriotism and the nationalist referendum, against our beloved United Kingdom, and our reply as God's people this time is 'no separation'."