# Yahweh was putting his enemies under the soles of his feet

"Yahweh was helping David to defeat his enemies" or "Yahweh was enabling David to completely defeat his enemies" 

# for the name of Yahweh

"in which people would worship Yahweh"

# because of the wars that surrounded him

"because of the wars with which his enemies surrounded him" or "because he was fighting enemies on all sides"