Photo from Thoth, God of Knowledge

The most important reason to marinate is to add flavors.  Here’s how a marinade works:  A good marinade is a blend of something acid (wine, citrus juices or vinegar), salty (soy sauce or fish sauce) and sweet (sugar, honey, maple syrup or jams) plus a variety of other seasonings such as garlic, herbs and chiles.  The acid softens the tissues so the meat fibers can separate and allow the marinade to penetrate, salt transports the liquid into the tissues and sugar helps hold it there.  The result is meat with lots more flavor, that is juicier and a just a bit more tender than nature made it.  Remember though – – – marination is done for flavor NOT to tenderize.