Agis and Cleomenes (Cleomenes.3.3-Cleomenes.3.4)

but when it was apparent that Cleomenes took an unusual interest in the story, and was profoundly stirred by the innovations of Agis, and wished to hear about him over and over again, Xenares rebuked him angrily, calling him unsound in mind, and finally stopped visiting and conversing with him. To no one, however, did he tell the reason of their variance, but merely said that Cleomenes understood it.

And so Cleomenes, finding Xenares averse, and thinking that everybody else was of like mind with him, began to arrange his project all by himself. And because he thought that he could better bring about his reforms in time of war than in the midst of peace, he embroiled the state with the Achaeans, who were themselves giving grounds for complaint. For Aratus, the most powerful man among the Achaeans, was from the outset desirous of bringing all the Peloponnesians into one confederation, and this was the end pursued by him during his many generalships and his long political activity,