1)
Why did he say "Ka'asher Ra'isi"?
1.
Malbim: I will mention many Resha'im who perished, and their names. Can you name me one Tzadik who was lost? A Tzadik is temporarily afflicted, to cleanse his sins, but he does not totally perish. When a Rasha's Midah [of sin] is full, he is totally lost. No Tzadik was lost like this. "A Tzadik falls seven times, and stands"!
2)
What plowing, seeding and reaping are discussed?
1.
Rashi: They plan evil, like one who plows prepares before seeding. Afterwards they seed in deed, and reap - their evil comes upon them. Such people were hidden and lost.
2.
Devar Eliyahu: They are a Mashal for thought, speech and action, respectively.
