en_tn_condensed/deu/04/09.md

Only pay attention ... guard yourself ... you do not forget ... your eyes ... your heart ... your life ... Make them known to your children and your children's children

Moses speaks to the Israelites as if they are one person, so all instances of "you," "your," and "yourself," as well as the commands "pay attention," "guard," and "make known" are singular.

Only pay attention and carefully guard yourself

"Pay careful attention and be sure to remember these things always"

you do not forget ... they do not leave your heart

These phrases means the same thing and emphasize that the people of Israel must remember what they have seen.

your eyes have seen

"you have seen"