It hath been ordained that every believer in God, the Lord of Judgement, shall, each day, having washed his hands and then his face, seat himself and, turning unto God, repeat “Alláh-u-Abhá” ninety-five times. Such was the decree of the Maker of the Heavens when, with majesty and power, He established Himself upon the thrones of His Names. Perform ye, likewise, ablutions for the Obligatory Prayer; this is the command of God, the Incomparable, the Unrestrained.

It hath been ordained that every believer in God . . . shall, each day . . . repeat
“Alláh-u-Abhá” is an Arabic phrase meaning "God the All-Glorious". It is a form of the Greatest Name of God (see note 137). In Islám there is a tradition that among the many names of God, one was the greatest; however, the identity of this Greatest Name was hidden. Bahá’u’lláh has confirmed that the Greatest Name is "Bahá".
The various derivatives of the word "Bahá" are also regarded as the Greatest Name. Shoghi Effendi’s secretary writing on his behalf explains that

The Greatest Name is the Name of Bahá’u’lláh. "Yá Bahá'u'l-Abhá" is an invocation meaning: "O Thou Glory of Glories!". “Alláh-u-Abhá” is a greeting which means: "God the All-Glorious". Both refer to Bahá’u’lláh. By Greatest Name is meant that Bahá’u’lláh has appeared in God’s Greatest Name, in other words, that He is the supreme Manifestation of God.

The greeting “Alláh-u-Abhá” was adopted during the period of Bahá’u’lláh’s exile in Adrianople.
The repetition of “Alláh-u-Abhá” ninety-five times is to be preceded by the performance of ablutions (see note 34).

Question: Do ablutions performed for the Obligatory Prayer suffice for the ninety-five repetitions of the Greatest Name?
Answer: It is unnecessary to renew the ablutions.