Why does it say "Al Tira Ki Imecha Ani"?
Refer to 41:8:1:1 and the note there.
Malbim: One can fear (a) Lest his beloved, who helps him constantly, now despises him. Do not fear this - "Becharticha v'Lo Me'asticha" (9). (b) Perhaps his beloved will not be found at a time of affliction. Do not fear this - "Ki Imecha Ani." (c) Lest his beloved not be able to save him. Do not fear this - "Ani Elokecha" who supervises over you.
What is the meaning of "Al Tishta"?
Rashi: Your heart should not melt, to be like Sha'avah (wax). Whenever the first letter of the root is Shin, in Hispa'el, a Tov separates it from the other letters of the root, e.g. "va'Yishtomem" (59:16).
Radak, Malbim: Do not fear,
Radak citing Targum Yonasan: Do not be broken.
Radak citing his father: This is from the root She'u; do not slacken from Me, like "Al Yirpu Yadecha" (Tzefanyah 3:16).
What is "Imatzticha"?
Malbim: I gave to you strength to stand by yourself against the enemy.
Why does it say "Temachticha bi'Ymin Tzidki"?
Malbim: This is like a lover who helps his beloved with his left hand, and supports him with his right hand, lest he fall. One hand supports, and one hand fights the enemy.
