Guide for the Perplexed, by Moses Maimonides, Friedländer tr. [1904], at sacred-texts.com
THE term kam (he rose) is a homonym. In one of its significations it is the opposite of "to sit," as "He did not rise (kam) nor move for him" (Esth. v. 9). It further denotes the confirmation and verification of a thing, e.g.: "The Lord will verify (yakem) His promise" (1 Sam. i. 23); "The field of Ephron was made sure (va-yakom) as the property of Abraham" (Gen. xxiii. 17). "The house that is in the walled city shall be established (ve-kam)" (Lev. xxv. 30); "And the kingdom of Israel shall be firmly established (ve-kamah) in thy hand" (1 Sam. xxiv. 20). It is always in this sense that the verb is employed with reference to the Almighty; as "Now shall I rise (akum), saith the Lord" (Ps. xii. 7), which is the same as saying, "Now shall I verify my word and my dispensation for good or evil." "Thou shalt arise (takum) and have mercy upon Zion" (Ps. cii. 13), which means: Thou wilt establish what thou hast promised, viz., that thou wouldst pity Zion.
Generally a person who resolves to set about a matter, accompanies his resolve by rising, hence the verb is employed to express "to resolve" to do a certain thing; as, "That my son hath stirred up my servant against me" (1 Sam. xxii. 8). The word is figuratively used to signify the execution of a divine decree against a people sentenced to extermination, as "And I will rise against the house of Jeroboam" (Amos vii. 9); "but he win arise against the house of the evildoers" (Isa. xxxi. 2). Possibly in Psalm xii. 7 the verb has this latter sense, as also in Psalm cii. 13, namely: Thou wilt rise up against her enemies.
There are many passages to be interpreted in this manner, but in no way should it be understood that He rises or sits--far be such a notion! Our Sages expressed this idea in the formula," In the world above there is neither sitting nor standing (‘amidah)"; for the two verbs ‘amad and kam are synonyms [and what is said about the former is also applicable to the latter].