Men take military oaths at 1940s ceremony

The transcript is a series of oaths taken by individuals to swear allegiance to the United States, promising to follow the orders of the President and appointed officers. It covers the commitment to serve honestly and faithfully, adhering to the rules and regulations of the Navy, Coast Guard, Army, and Marine Corps.

What is the significance of the phrase 'So help you God' in the oath?

What are the consequences if you do not follow the orders of the President?