Boēthos (βοηθός) is the noun/adjective for a helper — one who runs to aid another's cry. The word appears in Hebrews 13:6 as a quotation from Psalm 118:6, where the LXX uses it to translate the Hebrew ezer (helper). It describes God as the definitive Helper of His people.
"The Lord is my helper (boēthos); I will not fear; what can man do to me?" (Hebrews 13:6) — this declaration from Psalm 118:6 is the ultimate confidence statement of the believer. God is not a passive observer who wishes us well; He is our active Helper, running to our cry. This same word (in cognate form) is implied when Jesus calls the Holy Spirit the paraklētos — the Helper alongside us.