Why did she grab Elisha's feet?
Ralbag: It was to bow to him and request from him for her son.
Malbim: She hinted that she will not leave him until he goes with her.
Why did Gechazi want to push her away?
Radak #1: It was for her honor, lest she kiss his feet 1 .
Radak #2: It was for the Navi's honor, lest she hold his feet.
Malbim: It is improper for a woman to approach the Navi.
Brachos 10b learns from "LeHodfah" that he grabbed her by her "Hod" (most beautiful part). Perhaps he was motivated by lust, and the Meforshim's reasons (refer to 4:27:2:1-3) were mere excuses to push her! We find that Elisha knew what Gechazi intended to do with Na'aman's money (refer to 5:26:3:1). Also here, he knew that Gechazi had a proper reason to push her away, just his lust moved him to do so in a lewd way. Elisha hoped that Gechazi would improve. Had he acted purely due to lust, Elisha would have immediately expelled him from being his Talmid! (PF)
Why did he mention that Hashem hid it from him?
Radak: He hid it until now; now Hashem told him via Nevu'ah.
Malbim: When Hashem punishes, he tells Nevi'im first, so they will request mercy - "ha'Mechaseh Ani me'Avraham Asher Ani Oseh" (Bereishis 18:17). Hashem hid this from me; this shows that it is not due to her sin.
