[7] On 30 March 1941, Hitler delivered a speech to about two hundred senior Wehrmacht officers where he laid out his plans for an ideological war of annihilation (Vernichtungskrieg) against the Soviet Union.

[9] As a commander of the 4th Panzer Group, he issued a directive to his troops:[10] The war against Russia is an important chapter in the struggle for existence of the German nation.

[11] The historian Jürgen Förster wrote that Hoepner's directive represented an "independent transformation of Hitler's ideological intentions into an order".

[14] The Red Army mounted a number of counterattacks against the XXXXI Panzer Corps, leading to the Battle of Raseiniai.

[16] Ultimately, the army group defeated the defending Soviet Northwestern Front, inflicting over 90,000 casualties and destroying more than 1,000 tanks and 1,000 aircraft, then advanced northeast of the Stalin line.

[17] On 6 July 1941, Hoepner issued an order to his troops instructing them to treat the "loyal population" fairly, adding that "individual acts of sabotage should simply be charged to communists and Jews".

The staff and detachments 2 and 3 of Einsatzgruppe A, one of the mobile killing squads following the Wehrmacht into the occupied Soviet Union, were brought up to the Luga district with assistance from the army.

A compromise solution was worked out whereas the infantry would attack north from both sides of Lake Ilmen, while the panzer group would advance from its current position.

The 4th Panzer Group was to be the main attacking force, which reached south of the Neva River, where it was faced with strong Soviet counter-attacks.

[24] As part of Operation Typhoon, the 4th Panzer Group was subordinated to the 4th Army under the command of Günther von Kluge.

Kluge instructed Hoepner to pause the advance, much to the latter's displeasure, as his units were needed to prevent break-outs of Soviet forces.

Hoepner was confident that the clearing of the pocket and the advance on Moscow could be undertaken at the same time and viewed Kluge's actions as interference, leading to friction and "clashes" with his superior, as he wrote in a letter home on 6 October.

Heavy rains and onset of the rasputitsa (roadlessness) caused frequent damage to tracked vehicles and motor transport further hampering the advance.

[29] Lacking strength and mobility to conduct battles of encirclement, the Group undertook frontal assaults which proved increasingly costly.

[30] A lack of tanks, insufficient motor transport and a precarious supply situation, along with tenacious Red Army resistance and the air superiority achieved by Soviet fighters hampered the attack.

The attack by the 2nd Panzer Group on Tula and Kashira, 125 km (78 mi) south of Moscow, achieved only fleeting and precarious success, while Guderian vacillated between despair and optimism, depending on the situation at the front.

[32] Facing pressure from the German High Command, Kluge finally committed his weaker south flank to the attack on 1 December.

In the aftermath of the battle, Hoepner and Guderian blamed slow commitment of the south flank of the 4th Army to the attack for the German failure to reach Moscow, grossly overestimating the capabilities of Kluge's remaining forces, according to Stahel.

[33] It also failed to appreciate the reality that Moscow was a fortified position which the Wehrmacht lacked the strength to either encircle nor take in a frontal assault, again according to Stahel.

The next day, he warned Kluge that failure to break off the attack would "bleed white" his formations and make them incapable of defence.

It then was able to halt the Soviet winter offensive in Southern Russia and then counterattacked in the Third Battle of Kharkov, retaking the city in March 1943.

It then fought a series of defensive battles throughout the remainder of 1943 to hold back the Red Army's Lower Dnieper Strategic Offensive Operation.

The army defended positions in Ukraine west of Kiev until late June 1944, fighting in the southern regions of the Pinsk Marshes, and around Lutsk, Shepetovka, Tarnopol, and Kovel in western Galicia.

The remnants of the army retreated along the entire front before re-grouping on the western bank of the Oder River in February 1945.

The Red Army then encircled this force in a pocket in the Spree Forest south of the Seelow Heights and west of Frankfurt.