As Christians we are to be people of singular focus- consider the following summary-

One thing to know:

One thing I do know, that though I was blind, now I see. (John 9:25b)

One thing is necessary:

Mary . . . sat at the Lord’s feet and listened to his teaching. But Martha was distracted with much serving. And she went up to him and said, “Lord, do you not care that my sister has left me to serve alone? Tell her then to help me.” But the Lord answered her, “Martha, Martha, you are anxious and troubled about many things, but one thing is necessary. Mary has chosen the good portion, which will not be taken away from her.” (Luke 10:39-42)

One thing to do:

Brothers, I do not consider that I have made it my own. But one thing I do: forgetting what lies behind and straining forward to what lies ahead, I press on toward the goal for the prize of the upward call of God in Christ Jesus. (Philippians 3:13-14)

One thing to ask for:

One thing have I asked of the LORD , that will I seek after: that I may dwell in the house of the LORD all the days of my life, to gaze upon the beauty of the LORD and to inquire in his temple. (Psalm 27:4)

(HT: Justin Taylor)