No. Being sanctified is not only found in the New Testament. The idea of being made holy and set apart for God runs through the Old Testament as well as the New, so it is not unique to the New Testament.
Old Testament foundation
It is a mistake to think sanctification appears only in the New Testament, because the theme is deeply rooted in the Old. The Old Testament repeatedly calls God’s people to be holy—language that expresses being set apart for God and belonging to him.
Key Old Testament verse
“You shall be holy; for I Yahweh your God am holy.” (Leviticus 19:2)
This command shows that the call to holiness is present in the Old Testament itself. When Scripture calls God’s people to be “holy,” it communicates the idea of being made holy and set apart for God—an idea that is central to what Christians often summarize as sanctification.
New Testament development
While the concept does not begin in the New Testament, the New Testament develops sanctification by describing the believer’s growth in holiness through Christ and the Spirit. In other words, the New Testament continues and unfolds the same holiness theme, presenting it in connection with Christ and the Spirit and speaking of holiness as a real, lived growth in the believer’s life.
Correcting a common assumption
A common assumption is that “sanctification” is a New Testament-only teaching. That assumption is mistaken. The Old Testament already contains the repeated call for God’s people to be holy, and the New Testament builds on that foundation as it describes the believer’s growth in holiness through Christ and the Spirit. So the theme spans both testaments rather than beginning in the New.
Frequently Asked Questions
Is sanctification only a New Testament idea?
No. The idea of being sanctified—made holy and set apart for God—runs through the Old Testament as well as the New, so it is not unique to the New Testament.
Where does the Old Testament teach holiness?
The Old Testament repeatedly calls God’s people to be holy. A clear example is Leviticus 19:2: “You shall be holy; for I Yahweh your God am holy.”
What does Leviticus 19:2 say?
“You shall be holy; for I Yahweh your God am holy.” (Leviticus 19:2)
This verse expresses the Old Testament call to holiness, which is central to the broader biblical theme often described as sanctification.
How does the New Testament talk about sanctification?
The New Testament develops sanctification as the believer’s growth in holiness through Christ and the Spirit. It continues the biblical call to holiness and presents that growth in connection with Christ and the Spirit.
How should the two testaments be related on this topic?
The concept spans both testaments rather than beginning in the New. The Old Testament repeatedly calls God’s people to be holy, and the New Testament develops sanctification as growth in holiness through Christ and the Spirit.