Justification, from the Latin justificare (‘to make just’), denotes a singular act of establishing something as right or fair: a fixed state of affairs.
Sanctification, rooted in sanctificare (‘to make holy’), describes a continual process of ‘setting apart’ or refining: gradual improvement.
Thus, justification fixes status, while sanctification implies an evolving condition.
Naturally used to discuss religious salvation, the terms provide a nuance between one-time justice and ongoing progress. However, both demand a ritual of public demarcation: a singular point from which forward movement can begin.