1) Repentance in practice. This means that he tries to observe all the practices, meaning the practice of learning and engaging in Torah and Mitzvot [commandments] properly.
Repenting means that before he repented, when he still did not observe all the Mitzvot as they should be. But after he repented, he observes the whole of Torah and Mitzvot as they should be. However, all this is only in the practice. In the intention of the Torah and Mitzvot, he still hasn’t repented.
2) Repentance in the intention. This means that before he repented in the intention, his aim was to receive reward. Now he regrets the aim he had before, and now he does everything not in order to receive reward, but only in order to bestow.
It follows that there is revealed work, to observe Torah and Mitzvot in practice, since a practice is revealed to all, and there is work in intention, which is concealed, since the aim is hidden from people.