Knowing, brethren beloved, your election of God.
Knowing - as we know. The three participles (1 Thessalonians 1:2-4) give the time, manner, and reason for 'giving thanks' (1 Thessalonians 1:2).
Your election of God - rather х eegapeemenoi (G25) hupo (G5259) Theou (G2316)], 'beloved by God:' so Romans 1:7. "Your election" - i:e., God elected you, as individual believers, to eternal life (Romans 11:5; Romans 11:7; Colossians 3:12; 2 Thessalonians 2:13).