940 B
of their own free will
"by their own choice." This means that they will chose to follow the king.
on the day of your power
This refers to the day that the king will lead his armies into battle. This can be stated clearly. AT: "on the day that you lead your armies into battle" (See: rc://en/ta/man/translate/figs-explicit)
from the womb of the dawn ... like the dew
David describes the dew as a baby to whom the dawn gives birth. AT: "in the morning ... like the dew" (See: rc://en/ta/man/translate/figs-personification)
from the womb of the dawn your youth will be to you like the dew
David is telling the king that he will have youthful strength each morning by comparing it to how the dew appears early each morning. AT: "each morning you will be filled with youthful strength to sustain you just like each morning the dew appears to water and sustain the earth" (See: rc://en/ta/man/translate/figs-metaphor)