What science says about the First Law of Thermodynamics.
The first law of thermodynamics is often called the Law of Conservation of Energy. This law suggests that energy and matter can be transferred from one system to another in different ways, BUT, it can not be created or destroyed. Thus, the total amount of energy and matter available in the Universe is constant. Einstein’s famous equation (written below) describes the relationship between energy and matter.
E = mc2
In the equation above, Energy (E) is equal to Matter (m) times the square of a constant (c). Einstein suggested that energy and matter are interchangeable. His equation also suggests that the quantity of energy and matter in the Universe is fixed.
To sum it up then, this first law is fairly easy to understand. Nothing, including energy or matter, can come from nothing, and neither matter nor energy can cease to be.