Here the 1906 LDS large-print edition replaced retained with obtained. This is undoubtedly a typo caused by visual similarity between the two words and possibly the influence of the following occurrence of maintain. The semantics for the verb obtain don’t really work in this passage, but retain works well enough with its normal meaning ‘keep’. The 1906 edition was never used as a copytext; thus the secondary obtained was never copied into any subsequent LDS edition.
For many cases in the original text, the verb retain had the meaning ‘take back’ or ‘regain’ (although not here in Alma 59:10). For most of these other cases, retain has been emended to regain or to verbs similar in meaning, especially in the LDS text. For an extensive discussion, see under Alma 58:3.
Summary: Maintain in Alma 59:10 the use of the verb retain, with its meaning here of ‘keep’.