ישראל עד השם אלקיך – Come all the way back to Hashem.
The real teshuva that Hashem wants from you is to come back close to Him. For this reason He has given His Word to mankind, so that they can find the right way to come to Him.
The pursuit of shleimus, the perfection of trying to get close to Hakodosh Boruch Hu, is a life long endeavor.
Moshe Rabeinu tried all his life; and although he succeeded enormously, nevertheless he didn’t fully succeed. Nobody can succeed completely. שובה ישראל עד השם – Come back to Hashem means not merely to stop doing aveiros. Hashem wants you to be perfect, as perfect as you can be. And that perfection means returning to Him by keeping Him before you all the time. All day long. That’s teshuva.