The meaning originally shown by the character 德 originally is not the ethical notion of virtue attributed to it in later times. For its understanding one has to go back to the world of early animism and curse magic.
The character 行 shows a crossroad and 彳. The classifier of 徳 is its left half and means a junction. As place where a lot of people pass, it is an important spiritual place, too. Naturally, accidents occur more frequently there, which is why it becomes an object for the exorcism of evil spirits.
As in the case of 蔑 or 省, the 目 (including the strokes above) which is seen in horizontal position in the right upper part of the character shows curse decoration. 省 means to show military power towards a region or country. Its upper part and the upper right part of 徳 has the common origin of patrolling with eyes that have curse power. What concerns the character 徳, from containing the element 彳 the objects of patrol conducted by eyes with curse decoration are the evil spirits at crossroads and junctions; it shows them being exorcised and ‘tadasu: put right’ again.
Previous character forms are often close to that of antiquity. Here, 徳, the form of the Common Use Characters since 1948 has one stroke less than its previous form 德 and is a form close to that of the bronze inscriptions.
Later, 心 was added to the character form for the first time on the bronze vessel 大盂鼎 ‘Dà Yú Dĭng: Big Tripod (made by) Yú’ in a long inscription amounting to 290 characters from the early period of the Western Zhōu dynasty, directly after the Yīn (Shāng)-Zhōu revolution. From this time on, the meaning of 徳 changed from referring to the curse power of the eyes toward the mental inner virtue as existing in the mind.