Who does "Achad ha'Am" refer to?
Rashi: It refers to Avimelech himself - since "Achad ha'Am" implies the one among the people who is unique (the king).
Targum Yerushalmi: It is a youth. (Youths are lightheaded, and liable to sleep with her.)
Yitzchak said that he feared being killed! Why did Avimelech rebuke him for saying that she is his sister?
Malbim: Due to concern for a possible danger to yourself, you should not have put us in certain danger! Ha'amek Davar - the esteemed and rich often enter your house. One could lie with your wife! Malbim - We remember that HaSh-m was ready to kill [me, or my father] for taking Sarah (20:7)!
QUESTIONS ON RASHI
Rashi writes: "You will bring guilt upon us - If he would have lain [with her], you would have brought guilt upon us already." Why does Rashi explain in the past tense?
Gur Aryeh: The guilt would come immediately upon such a deed, not in the future. Therefore, Rashi must explain in the past tense. 1
The word" v'Heiveisa" is accented mile'Ra (on the last syllable), which usually indicates a Vav ha'Mehapeches, switching the word to future tense. In this case, however, it means a conditional result - 'Had he done so, he would already be guilty.' (CS)