The repenting of the one who is on the path of Tazkiyah is a progressive repenting. Every time he repents, he is repenting from the past state of the heart to reach a better state. With each repenting, he gets better in Tazkiyah. In contrast, when a person who is not taking Tazkiyah seriously repents, he usually repents from the same sin or the same state of heart. Each time he repents, he corrects himself and goes back to the same starting point again. While the former moves upwards every time he repents, the latter simply repents in his effort to not go down further.
Both types of repenting, if sincere, is valuable and commendable. Both involve feeling pity for the shortcomings, a feeling of guilt and asking the Almighty for forgiveness in a most passionate manner. However, the difference between the two is like the difference between a wave in an ocean and a ripple in a pond. The latter may rise an inch or two at most whereas the former can reach the sky. Sometimes there can also be an issue with the second type of repenting. Repenting from the same sin over and over may be due to not perceiving that sin as something serious. This means committing that sin gradually becomes something normal for the person and therefore his repenting will be nothing beyond saying a few words. In other words, he does not really repent, he remains merely a sinful person who happens to say the words of repenting in between his sins!
A person who performs this second type of repenting is called a ‘Ta’ib’ (the one who repents) whereas a person who is involved in the first type of repenting (that is, a progressive repenting), is known as a ‘Tawwab’ (the one who repents continually). God particularly likes those people who are Tawwab (Qur’an, 2:222).
(Dr Abdullah Rahim)