# Go to your father's concubines

"Have sexual relations with your father's concubines" or "Lie with your father's concubines"

# to keep the palace

"to take care of the palace"

# become a stench to your father

"become offensive to your father" or "greatly insulted father" 

# Then the hands of all who are with you will be strong

"The news of this will strengthen the loyalty of all who follow you"