"the equation generally tells us that energy and mass that is the matter are interchangeable. We can also say that they are different forms of the same thing. That is said to be under the right conditions, energy can generally become mass and vice versa. We humans usually don't see them that way but we can ask that how can a beam of light and a walnut be different forms of the same thing?—but Nature does.
mc2 Equation
The equation that is E = mc2 is of physicist Albert Einstein’s theory which is of special relativity expresses the fact that mass and energy are the same physical entity. And these entities can be changed into each other."
https://www.vedantu.com/physics/e-mc2-equation
"E = mc2 Special Relativity Equation
This equation states that energy equals mass times the speed of light squared.
E=mc2
Where:
E = energy
m = mass
c = speed of light
The Meaning of E = mc2
The E = mc2 equation represents the idea that energy and mass are correlated, that any object with mass corresponds to an equivalent amount of energy. This equation is Einstein's special theory of relativity in mathematical terms."
https://www.calculatorsoup.com/calculators/physics/emc2.php
"the law of vibration, posits that everything (every atom, object, and living thing) is in constant motion, vibrating at a specific frequency."
"You can think of this frequency as vibrational energy"
https://www.mindbodygreen.com/articles/law-of-vibration
"Electromagnetic radiation can be described in terms of a stream of mass-less particles, called photons, each traveling in a wave-like pattern at the speed of light. Each photon contains a certain amount of energy. The different types of radiation are defined by the the amount of energy found in the photons."
https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html