In the course of his teaching he said, "Beware of the scribes, who like to go around in long robes and accept greetings in the marketplaces, seats of honor in synagogues, and places of honor at banquets. They devour the houses of widows and, as a pretext, recite lengthy prayers. They will receive a very severe condemnation." He sat down opposite the treasury and observed how the crowd put money into the treasury. Many rich people put in large sums. A poor widow also came and put in two small coins worth a few cents. Calling his disciples to himself, he said to them, "Amen, I say to you, this poor widow put in more than all the other contributors to the treasury. For they have all contributed from their surplus wealth, but she, from her poverty, has contributed all she had, her whole livelihood." (Mk 12:38-44)
This is an interesting episode. Jesus is seated opposite to the treasury. It is said that the money collected from this treasury was used for the maintenance and repair of the Temple. The money collected from the treasury that was within the Temple was used for the sacrifice and the services. Jesus was well aware that the money that was contributed by the widow would go for the maintenance.
In the following verses (of Chapter 13) Jesus speaks about the destruction of the Temple saying, ‘There will not be one stone left upon another that will not be thrown down’. We wonder why Jesus did not tell the widow not to throw the money in the treasury (because the money will, only be wasted because the Temple is going to be destroyed) in stead use it for her own upkeep.
The lesson that Jesus wants to teach through this is that one should be faithful even when he/she is aware that it is going to be wasted. Fidelity is more important. It is because of this that the widow is honoured by Jesus. Fidelity in spite of knowing that the efforts made are going to be wasted is the lesson.