Eternal Life Insurance

In 14:1 - זאת תהיה תורת המצורע ביום טהרתו - Why does the Torah use the future tense? Why is the Metzora's purification process called a "Torah?" If Dovid HaMelech says avoid evil and do good, why does he also say guard your tongue from evil, it's included? Was Moshe denied entry to Israel because of מי מריבה or for slandering Bnei Yisrael in Shemot?

Shiur provided courtesy of Torah Anytime