Seneca said this quote

“ And do you know why we have not the power to attain this Stoic ideal? It is because we refuse to believe in our power. Nay, of a surety, there is something else which plays a part: it is because we are in love with our vices; we uphold them and prefer to make excuses for them rather than shake them off. We mortals have been endowed with sufficient strength by nature, if only we use this strength, if only we concentrate our powers and rouse them all to help us or at least not to hinder us. The reason is unwillingness, the excuse, inability. ”