Gruul War Plow — ruling 1

A noncreature permanent that turns into a creature can attack, and its {T} abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn't matter how long the permanent has been a creature.

Gruul War Plow — ruling 2

While it's a creature, Gruul War Plow gives itself trample.

Gruul War Plow — ruling 3

While it's a creature, Gruul War Plow has creature type Juggernaut. It doesn't have any abilities associated with the card named Juggernaut.

Gruul War Plow : règles, fonctionnement et interactions (MTG)

Gruul War Plow 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

Creatures you control have trample. : This artifact becomes a 4/4 Juggernaut artifact creature until end of turn.

How it works : Gruul War Plow

Original English text — Wizards of the Coast / Scryfall

#1August 1, 2008· Wizards of the Coast
A noncreature permanent that turns into a creature can attack, and its abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn't matter how long the permanent has been a creature.
No other card is named in this ruling.
#2February 1, 2006· Wizards of the Coast
While it's a creature, Gruul War Plow gives itself trample.
No other card is named in this ruling.
#3February 1, 2006· Wizards of the Coast
While it's a creature, Gruul War Plow has creature type Juggernaut. It doesn't have any abilities associated with the card named Juggernaut.
No other card is named in this ruling.