Isaiah 12:2 Behold, God is my salvation; I will trust, and not be afraid: for the LORD JEHOVAH is my strength and my song; he also is become my salvation. 

Matthew Henry Bible Commentary:

God is my salvation; 

not only my Saviour, by whom I am saved,

but my salvation, in whom I am safe.

and if God be my salvation, 

if he undertake my eternal salvation, 

I will trust in him to prepare me for it and preserve me to it. 

I will trust him with all my temporal concerns, not doubting but he will make all to work for my good.  

I will be confident, that is, I will be always easy in my own mind.

Note, Those that have God for their salvation may enjoy themselves with a holy security and serenity of mind. 

Let faith in God as our salvation be effectual, 

(1.) To silence our fears. 

We must trust, and not be afraid, not be afraid that the God we trust in will fail us; 

no, there is no danger of that; 

not be afraid of any creature, though ever so formidable and threatening. 

Note, Faith in God is a sovereign remedy against disquieting tormenting fears.

Proverbs 18:10 The name of the LORD is a strong tower: the righteous runneth into it, and is safe.