[26b middle] Rava: If someone saw a sela coin fall down, and he, before the owner despaired of recovering it, took it with intent to steal it, he transgresses all possible prohibitions (directly associated with returning lost objects) [including: “Do not steal,” “You shall surely return,” and “You may not look away.”]. Even if he would afterwards return the object to the original owner after he had despaired of recovering it, the thief is merely giving him a gift and is still considered as having sinned.
Rosh: Even the Mitzvah of ‘returning a lost object’ is not fulfilled when he does return the coin later. The unique solitary time of this commandment is only at the first occurrence of ‘finding’ it. If someone misses that critical moment, the Mitzvah is lost forever.
D-E-ep Thoughts: Although we have opportunities to do Teshuvah, there are still favorable times and Holy levels that we may never obtain if we do not seize them while they are readily available. Hashem is constantly showering us with limitless potential, but we have to open our eyes to see it. Even tests and challenges are only given to us through love. G-d’s blessing is for us to be able to overcome them and succeed, for through doing so, we will be elevating our spiritual status.