When did Giborim from Gad come to David?
Malbim: It was before Bnei Binyamin 1 came.
Perhaps he infers so due to the simple past tense "Nivdelu", and not future with the prefix Vov. Refer to Bereishis 4:1:1:1. (PF)
Why does it say "Nivdelu"?
Malbim: They were Sarei Tzava (verse 15). They abandoned their armies to go to David.
What is "la'Metzad Midbarah"?
'Rashi': It is the fortresses in the Midbar where he hid from Sha'ul ? "v'David va'Anashav b'Midbar Ma'on; ?v'Yeshev bi'Metzados Ein Gedi" (Shmuel I, 23:25, 29).
Malbim: It is the fortresses in Midbar Zif where he hid from Sha'ul ? "va'Yeshev David ba'Midbar bi'Metzados" (Shmuel I, 23:14).
Why does it say that their faces were like lions' faces?
'Rashi': They were scary like lions' faces.
Why does it say "uch'Tzeva'im Al he'Harim Lemaher"?
'Rashi': When one hunts deer, they run on mountains.
