1)
Why did he say both "Anochi ha'Ba Min ha'Ma'arachah" and "va'Ani Min ha'Ma'arachah Nasti"?
1.
Kli Yakar (Lani'ado, like Rabanan in Midrash Shmuel 11:1): He went 180 Mil that day. Initially he fled 60 Mil to Shilo, and did not give bad tidings. When he heard that the Aron was taken, he went back, seized the Luchos and returned to Shilo again.
2.
Malbim, like R. Simon in Midrash Shmuel 11:1: He went 120 Mil that day. He was near the Ma'arachah in Shilo, and he heard that the Aron was taken. He went to the Ma'arachah (battlefield), seized the Luchos and returned to Shilo.
2)
Why did he need to say that he came from the Ma'arachah today?
1.
Malbim: I myself saw, and today; I did not forget anything.
