Lots of people (myself included) do not fully understand or grasp the Trinity of God. The Triune (that is, three + union, I believe) nature of God says that although there is one God, there are three distinct persons of God (Father, Son, and Holy Spirit) that coexist all at the same time (as opposed to being various modes/forms) and are all equally and wholly God. If your head’s not spinning even just a little right now, go back and reread.
Anyway, I thought of the following illustration (involving some basic Chemistry knowledge) to try to understand it better myself as well as maybe explain it to others in a way that might be helpful. Here goes:
We all know that we need water to live. Water is a more or less staple ingredient necessary for life. It allows for important cell processes such as hydrolysis and photosynthesis, as well as regulating the cell’s internal conditions in terms of temperature so that enzymes can have optimum functioning conditions. Pretty much every living thing needs water in some form to live.
Water also happens to be the only substance (as far as I know, anyway) that can simultaneously exist in all three states of matter at the same moment and in the same environment. At zero degrees Celsius, water exists as a solid (for example, ice in a cup), a liquid (water in the cup), and a gas (water vapour in the surrounding air). And yet, the three iterations of the delicious substance are just as much hydrogen-oxygen-hydrogen as the next. Thus, three different “phases” (solid, liquid, gaseous) coexisting simultaneously but one single “what”: dihydrogen oxide.
Does that help or does the Chemistry make it worse?