All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
The meaning of the phrase, "'antal Baatinu fa laysa doonaka shaya'" is that Allaah, The Exalted, is the nearest to His creation and nothing is nearer to His creation than Him.
What is mentioned in the Quran and the Sunnah about the 'Uluww (Highness) and Aboveness of Allaah does not contradict His Nearness and His Ma'iyyah (being with His creation). The 'Uluww of Allaah and His Istiwaa’ on (mounting) His Throne are established by the Quran, Sunnah, and the scholarly consensus of the early Muslim generations . He is the Near in His Highness and the High in His Nearness; there is nothing like unto Him, and He is the Hearing, the Seeing. Ibn Jareer At-Tabari wrote, "Allaah is 'Al-Baatin', nothing is nearer to His Creation than Him, as He says (what means): {...and We are closer to him than [his] jugular vein.} [Quran 50:16] This has been evidenced by the statements of the Prophet and confirmed by the commentators of the Quran." [Jaami’ Al-Bayaan 23/168]
Ibn Al-Qayyim wrote: "Therefore, Allaah, The Exalted, couples the two names that indicate those two meaning: 'The Most High' - (nothing is above Him) - and 'The Most Great' - (nothing is more encompassing and nearer than Him). Allaah, The Exalted, says (what means): {... And He is the Most High, the Most Great.} [Quran 2:255] {... And He is the Most High, the Grand.} {And to Allaah belongs the east and the west. So wherever you [might] turn, there is the Face of Allaah. Indeed, Allaah is All-Encompassing and Knowing.} [Quran 2:115] Just as Allaah, The Exalted, is the Most High, above all the Creation and nothing is above Him, He is also the Nearest to His Creation and nothing is nearer to them than Him; He is closer to His creation than their own selves. He has full control over the whole universe and has power over all things; He encompasses all things in His knowledge. (Nothing of His creation can encompass Him and He is not contained within His creation.) ...” [Tareeq Al-Hijratayn wa Baab As-Saʻaadatayn: p. 22]
Allaah Knows best.