The word sila has several meanings depending upon the context in which it is used.
Most teachings concerned with ethics affirm the non-doing of evil and the cultivation of good.
The Buddha's teaching, however, adds a further dimension to the realm of ethics, that of purification of mind. This means purifying the mind of selfishness - of all tendencies and references to self or selfhood. This is accomplished through the sequential development of morality, which gives rise to collectedness of mind, which in turn gives rise to liberation. So indeed, Ananda, wholesome conduct gradually leads on to the highest. The impersonal and automatic Law of Kamma is what judges a Buddhist's actions, so rather than trying to cover up wrong-doing, the most that can be done is to do good actions to counteract the wrong.