Note 17 at Eph 5:9: In Eph 5:8, Paul was promoting holiness, because that's the nature of a Christian (see note 15 at Eph 5:8). Here, he gave us another reason for living godly lives. It's because the fruit of the Spirit is borne in all goodness, righteousness, and truth.

Ungodliness inhibits the growth of the fruit of the Spirit in our lives. That's not because God's love is conditional. His love for us is unconditional. But just as seeds cannot grow without light, so the darkness of ungodliness in our lives limits the production of the fruit of the Spirit. If we cultivate a life of hatred, the fruit of love (Ga 5:22) will not manifest. If we are truly born again (see note 2 at Joh 3:3), that love is present in our spirits, but it cannot flow while we are operating in hatred.