John Wesley preached entire sanctification as attainable, not automatic. In his sermon Christian Perfection, one of his standard sermons, he was careful to list what the state does not include. It does not mean freedom from ignorance, since a perfected believer can still be mistaken about facts. It does not mean freedom from mistake, since judgment can err even where the will is right. It does not mean freedom from the infirmities of body or temperament, the kind of weakness tied to a person's constitution rather than their choices. And it does not mean the believer can no longer fall, since Wesley insisted the state had to be watched and could be lost through neglect.
What Wesley did claim was narrower and more precise: a heart so filled with love for God and neighbor that it no longer chooses sin knowingly. He drew the line at intention rather than performance, arguing that a mistake made in ignorance is not the same thing as a sin committed against known duty. This distinction let him hold together two things that looked contradictory to his critics, that a believer could be entirely sanctified and still need the daily prayer for forgiveness in the Lord's Prayer, understood as covering unintentional fault rather than willful transgression. Wesley taught the experience could come gradually, as a process of growth in grace, or instantaneously, as a further definite work of grace following justification, and he refused to insist on either pattern as the only true one.