אָדָם כִּי יַקְרִיב מִכֶּם קָרְבָּן לַה' מִן הַבְּהֵמָה מִן הַבָּקָר וּמִן הַצֹּאן תַּקְרִיבוּ אֶת קָרְבַּנְכֶם
When a man (singular) brings an offering to Hashem: From the animals - from the cattle or from the flock shall you (plural) bring your offering (1:2)
Why is there a sudden change of tense from singular to plural in this verse?
Rav Moshe Shternbuch learns from here that when a person sins, it not only affects himself, but also the public as a whole. Consequently, when he brings a sacrificial offering and amends his actions, the blemish which attached to the nation also becomes removed – and the entire nation becomes elevated as a result. Therefore, Rav Shternbuch explains that the beginning of the verse is referring to the individual sinner wishing to repent and the end of the verse comes to show that his sacrifice will have an effect on the whole world. Because, once the world becomes elevated through this person’s repentance, Hashem showers an abundance of blessing on the whole world and the whole nation becomes purified.
Rav Zev Leff is fond of telling the following analogy which expresses Rav Shternbuch’s point.
A father was sitting comfortably in his chair, trying read his magazine when his five year old daughter comes tugging on his jacket, she was bored. So, the father ripped out one of the pages from his magazine which happened to be a map of the world and tore it into 25 pieces. He gave it to his daughter and told her to come back to him when she has completed the “jigsaw”. Assuming that it would take her an hour to match the contours of each rip of the paper, he was amazed to see his daughter had returned after a few minutes with a completed picture of the map of the world.
“How could it be, you’ve never even seen the map of the world? How could you have done it so quickly?”
“It was easy” answered his daughter “I did not know how to piece the world together, but on the other side of the page was a picture of a person. Once I put the person together, the whole world fell into place!”
From this example, and like we have seen from the verse above, if you want to change the world, all you need to do is to change yourself.
From Shortvort.com