Does Ephesians 4:30 Preclude the Loss of Our Salvation?

In his Letter to the Ephesians, St. Paul writes, “And do not grieve the Holy Spirit of God, in whom you were sealed for the day of redemption” (Ephesians 4:30).

Read in isolation, one might infer that we might not be able to lose our salvation, yet even in this passage Paul notes that we can sin against the Holy Spirit. Jesus teaches that the sin of the Holy Spirit cannot be forgiven, and the Church has always understood this sin to be “final impenitence,” i.e., mortal sin for which we do not seek forgiveness (CCC 1864).

Similarly, St. Paul addresses the reality and consequences of unrepentant mortal sin in Romans 2:3-11.