God will send Jesus Christ back at His appointed time. Paul"s doxology (a statement glorifying God) emphasized His adorable and unique sovereignty, immortality, and incomprehensible holiness (cf. Exodus 24:17). To Him belong all honor and rule throughout eternity (cf. 1 Timothy 1:17). [source][source][source]
"Ephesus was not only the haven of Artemis, but an early center of emperor worship as well. This doxology, therefore, is Paul"s parting shot that the God with whom the church has to do in the gospel of Christ is none other than the supreme Ruler of the universe, the Lord over all other lords." [1][source]