Translation:

3. Verily your Lord is Allah Who created the heavens and the earth in six Days and is firmly established on the Throne (of authority) regulating and governing all things. No intercessor (can plead with Him) except after His leave (hath been obtained). This is Allah your Lord; Him therefore serve ye: will ye not celebrate His praises?

Notes (Tafseer)

1385. See note 1031 to vii. 54.

1386. Istawa, with the preposition ila after it, means He turned to or He directed Himself by His will to as in ii-29. With the preposition 'ala after it, as here and in vii. 54 and elsewhere, the meaning seems to be "to mount or ascend," and to be firmly established, to sit firm and unshaken, beyond question. "The Throne represents many ideas: e.g., (1) that God is high above all His Creation; (2) that He regulates and governs it, as a king does, whose authority is unquestionably recognised; (3) that He is not, therefore, like the gods of Greece, and paganism, who were imagined to be in a world apart, careless of mankind, or jealous of mankind, but on the contrary. He (4) disposes of their affairs and all affairs continuously and with justice; (5) that the authority of His prophets, ministers, and messengers is derived from Him, and such intercession as they can make is by His will and permission.

1387. Cf. vi. 80.