Why did Moshe select only 'Anshei Chayil' out of all the Midos that Yisro mentioned (in Pasuk 21)?
Seforno: Because, unable to find anyone with all the Midos, he opted for Anshei Chayil 1 as judges. 2
Oznayim la'Torah: Because Moshe took for granted that that generation 3 were all Yir'ei Hashem, "Anshei Emes" 4 and "Son'ei Batza". 5
Seforno: Over and above even Yir'ei Elokim, because knowledge and diligence take precedence over the fear of G-d in such matters - as the Gemara indicates in Shabbos, 63a.
See also Rashi in Devarim (1:15).
Oznayim la'Torah: About whom the Torah testified "Vayir'u ha'Am es Hashem".
Oznayim la'Torah: Since he had taught them all Torah.
Oznayim la'Torah: Seeing as they had all their needs seen to. See Oznayim la'Torah, who also explains why Yisro thought otherwise.