This is the 5516th most frequent Japanese word.
およば
"およば" is a verb stem of "及ぶ" (oyobu), meaning "to reach" or "to extend to."
及ばない (oyobanai) is used here to indicate 'not being able to reach or match' a certain level, specifically someone's ability.
彼の能力には及ばない。
I can't match his ability.
及ぶ (oyobu) here means 'to reach or extend to,' suggesting that consultation extends to the extent required to address the issue.
その問題を解決するには、相談するに及ぶことです。
To solve that problem, consulting is essential.
及ぶ (oyobu) is employed to imply 'being worthy of' or 'extending to,' used here to indicate deserving merit or praise.