For the phrase “With the Lord on my side I do not fear. What can mortals do to me?” see Hebrews 12:15.
Note that this quote in the New Testament is not taken from the Hebrew Bible but from the Greek Septuagint (LXX) which translates into English as “The Lord is a helper to me; I will not fear what a person may do to me.” (Translation by NETS — for the Greek version see the title’s tooltip)