Smerel, rabbi yaakov shapiro’s “the empty wagon” devoted an entire chapter to this issue – he has all the quotes there, including the two i mentioned, plus much more. Israel had an advantage in its advanced technology, weaponry, training and other factors. The surrounding arab armies were militarily inferior to Israel’s in almost every aspect.
Who am I to say who Hashem is with? Well, Hashem said so himself regarding an inmoral army “ולא יראה בך ערות דבר ושב מאחריך” – if there is an immoral matter in the ranks of a Jewish army, Hashem himself says He will turn away from us.