As a general he joined forces with Jan Smuts and Koos de la Rey and his Commandos played a major role at the Battle of Nooitgedacht (13 December 1900).

[3][4] Beyers had gained much prestige as a soldier and a statesman among the Afrikaners, and was recognized as one of the leaders of the Transvaal Boers, though with slightly less standing than generals Botha and Smuts.

[3] A man of fine physique, of passionate nature, and of profound religious convictions, Beyers, as commandant general of South Africa, was entertained with marked attentions during his visit to Germany by Kaiser Wilhelm II.

[3] When World War I broke out, he set himself in almost open opposition to the policy of the First Cabinet of Louis Botha of the Union of South Africa.

When the South African expeditionary force was being mobilized for the invasion of German South-West Africa, with rebellion was smouldering among the irreconcilables of the South African Dutch, Beyers resigned his post as commandant general in a letter addressed to General Smuts, then Minister of Defence, and published in Het Volk, an anti-government journal.

General Smuts replied in a stern letter stating that the war was a test of the loyalty to their pledged word of the Dutch-speaking people, and accepted Beyers' resignation.

[3][5] In Beyers' pocket was found his prayer book “Worship God” written by the Reverend Andrew Murray, spectacles, cartridges for his Boer War Mauser pistol, and an important document on the rebellion.