In the times of the Bais Hamikdash, Jewish landowners were required to separate from their produce three kinds of tithing: terumah, a gift for the Kohanim, maiser rishon, the first tithe which is given to the Levi, and maiser sheni, which the farmer himself would go to Jerusalem and eat. And in the third and sixth years of every seven-year Shmittah cycle, the farmer would replace maiser sheni with maiser anni, the tithe for the poor.
In this, the second aliyah, the Torah gives the procedure to be followed every three years when the farmer is to declare that he has performed all his tithing properly. At the end of the aliyah we find that when the farmer finishes his declaration that he has done all the tithing properly, he then asks G-d to look down from His Holy residence in heaven, and bless the people and the land.
