And there is a difference betweeen whether a geminate verb contains all of the letters in its root or if its middle letter becomes swallowed with a דגש (diacritic dot), like יחל יחלל. יסב יסובב. צמת צמיתות. כרת כריתות, etc. Whenever the last letter is repeated, it teaches about the advantage of the action or its repetition.

Leviticus 22:2 says, דבר אל אהרן ואל בניו וינזרו מקדשי בני ישראל ולא יחללו את שם קדשי אשר הם מקדשים לי אני יהוה (Speak unto Aaron and to his sons, that they separate themselves from the holy things of the children of Israel, which they hallow unto Me, and that they profane not My holy name: I am the LORD), using the word יחללו for “profane”. The last letter of יחל is repeated, so it means several desecrations⁶⁹.

Leviticus 25:23 says, והארץ לא תמכר לצמתת כי לי הארץ כי גרים ותושבים אתם עמדי (And the land shall not be sold in perpetuity; for the land is Mine; for you are strangers and settlers with Me), using the word לצמתת for “in perpetuity”. The last letter of צמת is repeated, so it is interpreted to include that which is given as a gift⁷⁰.

footnotes: ⁶⁹ Malbim, HaTorah v’HaMitzvah Emor 65. ⁷⁰ Malbim, HaTorah v’HaMitzvah Behar 59.