When a Muslim makes a good Wudu and after that, does the five daily prayers, his sins drop just like the leaves of this tree

One day we were sitting under a tree, all of sudden he stood up and took and shook a branch of the tree which had dried leaves and all of its leaves dropped on the ground.

I got wondered; I said in my mind: why did he do that?

He looked at me and said: Salman! don't you want to know why did I do that?

I said:
Yes prophet of God, please tell me the reason of this action.

The holey prophet (Peace and Blessing be Upon Him and his family) said:
"When a Muslim makes a good Wudu and after that, does the five daily prayers, his sins drop just like the leaves of this tree."

After recited this vessel of Quran:

"and keep up prayer in the two parts of the day and in the first hours of the night; surely good deeds take away evil deeds this is a reminder to the mindful"
Surah: HUD 11:114