The thing about one thing is that if that thing is the right thing, then it regulates everything. Make the secondary in life primary and you lose out on both the primary and secondary. Make the primary primary, and you get it all! Several times in Scripture, the writers speak about "one thing."
One Thing Left
"This one thing I do, forgetting ..." (Phil 3:13). While we apply this Scripture to forgetting the failures of the past and moving forward, it actually has to do with what Paul could take pride in and from which he could derive a sense of significance. But so great was the goal - the knowledge of "Christ Jesus my Lord," - that anything which hindered had to be left behind. He had one all-absorbing passion which relegated everything else to secondary status. He did not debate whether this pleasure or amusement was right or wrong; if it hindered his goal, it was out!
One Thing Longed For
"One thing have I desired of the Lord ... to behold the beauty of the Lord" (Psa 27:4). David, although living before the full blaze of divine revelation as given in Christ, had soul longings after God which dwarf our tepid spiritual desires. Living amidst the opulence of his palace, surrounded by wealth and prosperity, all was secondary. His one desire was to appreciate increasingly the beauty of the Lord.
How much time do I spend gazing on the beauty of Christ? The Father found everything He ever longed to see in a Man in Him. It was not merely the absence of sin, but the presence of every virtue in all its fullness at every moment of time.
One Thing Lived For
"One thing is needful, and Mary hath chosen that good part" (Luke 10:42). Sitting at His feet and listening to His Word may seem to Martha - and perhaps to us - a failure to be "doing" things for the Lord. But a word from Christ readjusts all such values. The one thing which is good, is to enjoy His presence and His Word. Mary chose that good part, and nothing could take it from her.
Nothing can interfere with a souls enjoyment of Christ. Martyrs going to the fire have known it and imprisoned believers have enjoyed it. Sick beds, death beds, island exile, or a lonely widows room have all witnessed to the truth that His fellowship can be independent of earthly conditions. It is only our carnality which hinders and limits.
One Thing Learned
"Be not ignorant of this one thing, that one day is ... as a thousand years" (2Peter 3:8). As we leave behind all that would hinder and distract, longing for greater knowledge of Christ, and living for fellowship with Him, saints face trials and difficulties which do not afford easy answers. What strengthens believers to live expectantly is the realization of the program of a sovereign God: The "one thing" is that one day with the Lord is like 1,000 years (the power of God which can accomplish in one day what could take 1,000 years), and 1,000 years as one day (the patience and longsuffering of God). An awareness of His sovereignty puts all into perspective.
Live for one thing, and be sure it is the right "one thing."