I thank (χαριν εχω). "I have gratitude to." Common phrase (Luke 17:9), not elsewhere in Paul.

That enabled me (τω ενδυναμωσαντ με). First aorist active articular participle of ενδυναμοω. Late verb, but regular Pauline idiom (Romans 4:20; Philippians 4:13; Ephesians 6:10; 1 Timothy 1:12; 2 Timothy 4:17).

Appointing me to his service (θεμενος εις διακονιαν). Second aorist middle participle. Pauline phrase and atmosphere (Acts 20:24; 1 Corinthians 3:5; 1 Corinthians 12:18; 1 Corinthians 12:28; 2 Corinthians 3:6; 2 Corinthians 4:1; Colossians 1:23; Colossians 3:7; 1 Timothy 4:6; 2 Timothy 4:5; 2 Timothy 4:11).