We will have a two-front war with France and Russia. We will perform a small holding action while the rest of the army invades France by moving quickly through Belgium. We will then move on Russia.
Yes sir!To victory!
GERMANY
What actually happened...
We were not able to solely move our troops against Russia so we have to declare war on France. 
🇩🇪 Germany declares war on 🇫🇷France on August 3
Germany needed to cross through Belgium to go to France so they issued and ultimatum
Belgium! Allow our troops to pass through your territory or you will face the consequences!
Belgium was a neutral nation so they did not let them through 
We are sorry Germany but we are a neutral nation and we cannot let you through. 
🇧🇪
August 4. Great Britain declared war on Germany for violating Belgium's neutrality. All the great powers in Europe were at war. 
🇬🇧
We declare war on Germany for violating Belgium's neutrality! We are also afraid of losing our world power but no one has to know that.