During the seven day discussion between Hashem and Moshe, the question of Moshe’s worthiness for the task came up. The fear of the future leader, was that he was not a man of words, as he had a speech impediment.
Hashem reminds Moshe that He is the One that allows man to either be able to speak or not. He gives man the ability to hear or become deaf. He gives man wisdom and He gives man sight. He will be with Moshe, and he will succeed in his sacred mission.
The Talmud Yerushalmi in Masechet Brachot, explains that this verse is a hint to the miraculous manner that Moshe was able to escape Egypt after he killed the Egyptian hitting the Jew.
Aside from being saved from the sword of Pharoah, when his neck turned to stone, Moshe was saved in another way.
It was said in the name Rabbi Yehoshua Ben Levi that the entire population of Egypt, were stricken, to allow Moshe to escape. They temporarily lost use of their sense. They became deaf mutes, blind, and lame.
When they were asked where was Moshe, they could not speak. They asked others, and they could not hear the question. When asked if they saw Moshe, they were blind.
This is what Hashem reminded Moshe. Not only is He the One that gives man his five senses, but He showed Moshe how He was able to take away these senses, in order to save him.
If we rely on Hashem, with perfect faith, we will see salvation. We have nothing to fear.