so that through me the message would be fully proclaimed: Paul used his defense in court to share the good news about Jesus, similar to his past experiences (Acts 22:1–24:27; 26:1–29; see also 2 Timothy 2:9–10; Philippians 1:12–14).
all the Gentiles would hear it: Paul felt he had finished his mission (2 Timothy 4:7–8). The Old Testament prophesies the conversion of nations (for example, Psalm 22:27–29).
from the mouth of a lion: The lion often symbolizes enemies (see Psalms 7:2; 35:17; compare Daniel 6; Hebrews 11:33). Here, it might mean:
literal lions in the Roman theaters,
the emperor,
false teachers, or
Satan (1 Peter 5:8; compare Psalm 22:21).