What is "Netzach"?
Radak: It is forever and constant; it does not cease for me. Every day I am in a quarrel. It is as if my wound refuses to be healed; this is a metaphor. Why is this? What sin do I have?
Malbim: The anger that fills his Nefesh is like an internal wound in his Nefesh. He is constantly pained by the affliction of his nation. Refer to 15:18:3:3.
What caused his pain and Makos?
Radak (17): People disgraced him and cursed him to the point of hitting him.
What is "Anushah"?
Rashi: It is ill, like "va'Ye'anesh" (Shmuel II, 12:15; Bas Sheva's son fell ill).
Radak: It is like "Anushah Makoseha" (Michah 1:9) and "u'Che'ev Anush" (Yeshayah 17:11), i.e. strong.
Malbim citing Mahari: Some chronic illnesses have no pain and no danger, like Kadachas (fever) ha'Revi'is 1 . Some have pain but no danger; they are not chronic and not constant, like aching teeth and ears. Some are new and not old; they have no pain, but there is great danger, e.g. constant fever. Yirmeyah's illness has all the evils - pain, it is constant, it is dangerous, and there is no cure.
Mor u'Ketzi'ah (OC 328:101) says that this is dangerous; we may be Mechalel Shabbos due to it.
To whom does "Hayo Sihyeh Li" refer?
Rashi: It refers to Hashem. Radak - even though Hashem told Yirmeyah from the beginning (1:18) "I made you today a fortified city, iron pillar and copper wall", he did not think that they will fight him constantly.
What is "Achzav"?
Rashi: It is one whose reliance was cut off from him. You leave me to be pained via them. Achzav is a source that lacks or fails. Radak - the verse mentions the adjective 1 , but not the noun it describes (the source). We find like this - "k'Eder ha'Ketzuvos" (Shir ha'Shirim 4:2; it should say 'k'Eder Rechelos ha'Ketzuvos'. Rechelos is omitted), "u'Ma'achalo Beri'ah" (Chabakuk 1:16; its food is a fat Seh. Seh is omitted). Yonason added 'k'Maba' (like a spring).
Malbim: I am unlike other Nevi'im, whose Nevu'ah is constant, whenever they prepare themselves for it. I prophesize only sporadically, and after the Churban his Nevu'ah totally ceased. This is like a spring that totally ceased. Also refer to 15:18:6:2.
Radak: This is like Chazav; the Aleph is extra.
What is the meaning of "Mayim Lo Ne'emanu"?
Rashi: One cannot rely on them. Radak - this is a repetition of "Hayo Sihyeh Li Kemo Achzav" in different words.
Malbim: [Sometimes my Nevu'ah is like a source of] water that is not always available.
