Reduce in Stature — ruling 1

Reduce in Stature overrides all previous effects that set the creature’s power or toughness to specific values. However, effects that set its power or toughness to specific values that start to apply after Reduce in Stature becomes attached to the creature will override this effect.

Reduce in Stature — ruling 2

Effects that modify the power or toughness of the creature, such as the effects of Giant Growth or Honor of the Pure, will apply to it no matter when they started to take effect. The same is true for counters that change the creature’s power or toughness (such as +1/+1 counters) and effects that switch its power and toughness.

Reduce in Stature : règles, fonctionnement et interactions (MTG)

Reduce in Stature is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Enchant creature Enchanted creature has base power and toughness 0/2.

How it works : Reduce in Stature

Original English text — Wizards of the Coast / Scryfall

#1February 25, 2015· Wizards of the Coast
Reduce in Stature overrides all previous effects that set the creature’s power or toughness to specific values. However, effects that set its power or toughness to specific values that start to apply after Reduce in Stature becomes attached to the creature will override this effect.
No other card is named in this ruling.
#2February 25, 2015· Wizards of the Coast
Effects that modify the power or toughness of the creature, such as the effects of Giant Growth or Honor of the Pure, will apply to it no matter when they started to take effect. The same is true for counters that change the creature’s power or toughness (such as +1/+1 counters) and effects that switch its power and toughness.
No other card is named in this ruling.