RobH_en_tn/1ch/21/30.md

Now at that time ... the angel of Yahweh

Verses 29-30 are background information to explain why David offered this sacrifice at the threshing floor instead of on the altar at the tabernacle. (See: rc://en/ta/man/translate/writing-background)

to ask for God's direction

"to ask God to tell him what he should do"

afraid of the sword of the angel of Yahweh

Here "sword" represents being killed by the angel of Yahweh. Alternate translation: "afraid he would be killed by the angel of Yahweh" (See: rc://en/ta/man/translate/figs-metonymy)