The Arabic word tabaraka is very comprehensive, and cannot be understood fully and completely by "highly blessed", not even by a sentence. However, its meanings may be grasped by keeping in view the first two verses of Surah Al-Furqan:
تَبَارَكَ الَّذِي نَزَّلَ الْفُرْقَانَ عَلَى عَبْدِهِ لِيَكُونَ لِلْعَالَمِينَ نَذِيرًا
الَّذِي لَهُ مُلْكُ السَّمَاوَاتِ وَالْأَرْضِ وَلَمْ يَتَّخِذْ وَلَدًا وَلَمْ يَكُن لَّهُ شَرِيكٌ فِي الْمُلْكِ وَخَلَقَ كُلَّ شَيْءٍ فَقَدَّرَهُ تَقْدِيرًا
(25:1) Highly blessed is He, Who has sent down Al-Furqan, to His servant so that it may be a warner to all mankind.
(25:2) He to Whom belongs the Sovereignty of the heavens and the earth: Who has begotten no son: Who has no partner in His Sovereignty: Who created each and every thing and then ordained its destiny.
Here it has been used to convey the following meanings:
(1) He is the most Beneficent: that is why He has bestowed the great blessing of Al-Furqan by degrees on His servant so that he may admonish all mankind.
(2)He is the most Exalted and Great: for the Sovereignty of the heavens and the earth belongs to Him.
(3) He is the most Holy, Pure and Perfect: He is free from every tinge of shirk and has neither a partner in His Godhead, nor needs a son to succeed Him; for He is Ever-Lasting.
(4) He is the Highest and the Most Supreme in rank: the Kingdom and the Dominion wholly and solely belong to Him, and there is none who has any share in His Authority and Powers.
(5) He is the sole Creator of the universe and has created each and everything in it and predetermined its destiny.
In verse 25:10, Allah T'ala says:
تَبَارَكَ الَّذِي إِن شَاء جَعَلَ لَكَ خَيْرًا مِّن ذَلِكَ جَنَّاتٍ تَجْرِي مِن تَحْتِهَا الْأَنْهَارُ وَيَجْعَل لَّكَ قُصُورًا
(25:10) Highly blessed is He, Who, if He wills, could give you much more and better things than what they propose for you: (Not one but) many gardens, beneath which rivers flow; and big castles:
Here again the word tabaraka has been used and in the context it means: "AIIah has full control over everything and has unlimited powers: if he wills to favour somebody, He can do so as and when He wills without Iet or hindrance. "