창세기 26:8 해설: Rashi, Chizkuni, Rashbam & Kli Yakar

כי ארכו WHEN HE HAD BEEN THERE A LONG TIME — He thought, “From now I need have no fear since they have not molested her up to now”, and he was not sufficiently strict in guarding his actions (Genesis 20:13).

ויהי כי ארכו לו הימים, “it happened that his days were lengthened” seeing that Yitzchok had to abstain from marital relations for an extended period; it had become permissible for him to indulge in such relations even in daytime [to prevent involuntary ejaculation.] (Compare Bereshit Rabbah 64,5);

ויהי כי ארכו לו שם, after a while Yitzchok was no longer careful to conduct himself in a manner that the suspicion that Rivkah was his wife could not be aroused. The reason was that he did not think that she would be abducted.

וישקף אבימלך וגומר AND AVIMELEKH OBSERVED, ET CETERA — He saw him having sexual relations (Genesis Rabbah 64:5).