Here in the printer’s manuscript, Oliver Cowdery initially wrote “the Spirit of God”. Some time later, with uneven ink flow, he crossed out God and supralinearly inserted the Lord. The original manuscript is sufficiently extant here to determine that it read “the Spirit of the Lord”. Either reading is, of course, possible: there are 40 occurrences in the text of “the Spirit of the Lord” (including one of “the Spirit of the Lord Omnipotent”, in Mosiah 5:2) while there are 17 occurrences of “the Spirit of God”, including a nearby preceding one in Alma 18:16 (which may have prompted Oliver to initially write “the Spirit of God” here in Alma 19:14). For each instance of “the Spirit of God” and “the Spirit of the Lord”, the critical text will follow the reading of the earliest textual sources.
Summary: Maintain in Alma 19:14 the reading in 𝓞 (and the corrected reading in 𝓟): “the Spirit of the Lord”.