I’m willing to give people a pass when the same spelling can be pronounced two different ways. So here’s a tip:
Unless you’re penning a book for the Old Testament, do not use thee. Thee is a pronoun; the is an article. Please don’t ask me to explain what that means.
When speaking aloud, the (a th with one of those weird, upside-down e’s) should be used before words beginning with a consonant sound (the book, the team, the whole nine yards).
For words beginning with a vowel sound (the elephant, the iPhone, the underpants), you want to pronounce it with a long e, which would look like thee, but it’s still spelled the.
Simple, right? Whether you’re pronouncing it “thuh” or “thee”, it’s still spelled “the”. Any questions? Besides the article/pronoun thing?