en_tn_condensed/heb/03/14.md

For we have become

Here "we" refers to both the writer and the readers. (See: rc://en/ta/man/translate/figs-exclusive)

if we firmly hold to our confidence in him

"if we continue to confidently trust in him"

from the beginning

"from when we first began to believe in him"

to the end

This is a polite way of referring to when a person dies. Alternate translation: "until we die" (See: rc://en/ta/man/translate/figs-euphemism)