Sins can be classified into three – ones that we did in our previous Janmas, those that we do in this Janma and those that we are going to do in future. The moment you took this birth, the sins of your previous birth start yielding fruit and there is no escape from them. Hence you have no go but to experience its effects. However, by taking a dip in the Ganges, the sins of your current birth are wiped off.
It is for you to abstain from sinning in future, to avoid future sufferings.