New Defender's Study Bible Notes
3:13 one thing I do. “This one thing I do” is only one word in the Greek, succinctly expressing single-minded concentration and determination.
3:14 press toward. “Press toward” is the same as “follow after” in Philippians 3:12.
3:14 mark. The Greek word for “mark” here actually means “watch,” referring to being watchful for signs of the approaching end of the race.
3:14 prize. The “prize” is nothing less than God’s “crown of righteousness” which the Righteous Judge (II Timothy 4:7-8) will award those who have kept the faith and finished the course.