This is not an actual term in Scripture, but the truth that it conveys is definitely found in God’s Word. Christ’s Lordship is referred to in many places in the New Testament by the phrase—“in the Lord” (Rom. 16:2, 11-13, 19; 1 Cor. 7:22, 39; 9:1-2; 11:11; 15:58; 2 Cor. 10:17; Eph. 2:21; 4:1, 17; 5:8; 6:1, 10, 21; Phil. 2:19, 24, 29; 3:1; 4:1-2, 4, 10; Col. 4:7, etc.). Lordship has to do with the believer acknowledging Christ’s authority in his life practically.
In the epistles of Paul, “in the Lord” is different from “in Christ”—another expression that he often uses. “In Christ” refers to the believer’s position before God in Christ’s place of acceptance (Eph. 1:6; 1 John 4:17). It is an eternally fixed standing in which all Christians are in. (See In Christ.) “In the Lord,” on the other hand, has to do with the believer acknowledging the Lord’s authority in his life in practical matters. Hence, all Christians are “in Christ,” but all Christians may not be living their lives “in the Lord”—that is, as recognizing His Lordship authority over them practically.
Owning Christ’s Lordship in our lives means that we are not to just go out and do whatever we want to do, but to know from principles in the Word of God what the Lord would have us to do. Hence, Lordship applies to doing what He wants us to do in personal matters of conscience (Rom. 14:5-9), fellowship (Rom. 16:2, 19; Phil. 2:29), companionships and marriage (1 Cor. 7:39), the roles of men and women in the assembly (1 Cor. 11:11), walking in a way that would express the truth that the Church is the body of Christ (Eph. 4:1-4), children’s obedience (Eph. 6:1), travel plans (Phil. 2:24), service (Rom. 15:58; 16:11-13; Eph. 6:21; Col. 4:7), etc. Living practically under the Lordship of Christ is the secret of a happy, fruitful Christian life.