卫兵 means the the army is the guard of our country ,and also could refer to the guardsman of the army base.
神圣不可侵犯 means because they are protect our country, safety and lifes,they are honorable and should be respected.Thus we should not offend them.
神圣 means they are honorable.
不可侵犯 means could not offend them.
We respect soldiers although we hate war.We also have other sentences describe the relationship between the common and army.we say the soldiers are "最可爱的人" and all the soldiers have one purpose"为人民服务".these means the army serve people, and people love them.Hope it's useful.Thank you for reading it. :~）