The inner planets Mercury, Venus and Mars correlate with functions and qualities in the personality that are much like extensions of the Sun and Moon. (Sometimes the Sun and Moon are also included in the definition inner/personal planets.) In this respect, Venus mirrors qualities of the Moon - its nurturing, responsive symbolism of needs and emotions becomes in Venus the love-principle, romantic relating, personal values and most importantly the general reaching out (and being receptive to) other individuals in a more conscious way. By the same token, Mars seems to be a development of the Sun's idea. But where the Sun is core identity and will, the purpose and spirit of existence, Mars is desire pointed towards a specific objective and the will to act more than just to be. It focuses the self in immediate connection with the external or physical world.
Just as Venus represents "feminine" or "giving" principles and receptive love/sexuality, Mars represents "masculine", self-gratifying principles and active love/sexuality. The former mirrors the Mother-image of the Moon and the latter the Father-principle of the Sun. Mercury is the androgynous planet here, functioning as primary messenger and communicator (for the Sun's energies, mostly). It is a sort of middleman, harnessing impressions and feelings through the filter of the conscious rational mind. Mercury together with the Moon also controls semi-conscious/semi-instinctive reactive patterns that work somewhat on auto-pilot (presumably things like driving a car and speaking).
Below I give explanatory phrases for these three planets. The ambition is to show what kind of human processes and features the planets usually affect. The phenomena related to the planets below get their individual character and style by the sign and house placement, and not least the aspects of the planets.
The conscious and semi-conscious mind. Mentality: the style and color of the mind. The way we think, what we think about, mental patterns. Mental personality. Analytical intelligence. Categorizing and separating. The communication faculties. Language and the word as devices of the mind. Everyday, habitual affairs. Speaking and listening. The nervous system, fingers, hands and arms. Reason, understanding and expression. Channelling and relating experience from the five senses. The bridge between "higher" forms of mind (inner structure, patterns of thought, whole-seeing) and "lower" (single bits of information, cognitive and isolated facts, etc.) thus: Intelligence. Mercury is said to rule the zodiac signs Gemini and Virgo.
Mercury in aspect with other planets show mental preoccupations, traits, talents, gifts and qualities that color our individual mindset and mentality.
The love principle. The need for love, the capacity for loving. The style of loving. The act of appreciating. Values, sympathies and likings. Beauty, personal charm, attraction and grace. Platonic and friendly love. Sensation in a general sense. Selflessness. Giving, desiring (passively), wishing. Reaching out and including. Merging with others in search for harmony. The arts, in its experiencing and performing state (and the act of creating as different from pure inspiration). Beautification, decoration, entertainment, jewellery, luxury, glamour. Social attitudes and behaviour in small scale. Joy, pleasure and happiness. Aesthetics and form, clothing. Venus is said to rule the zodiac signs Libra and Taurus.
Venus in aspect shows influences from other planets inhibiting or aiding the love principle. It shows the style of expression in all matters of relating, as well as particular needs, capabilities and desires in the areas of beauty, art, creation and love.
The desire principle. Energy and initiating force. How we act (the manner in which we act), the target of our actions (what we want). One's resources and capabilities for action. Craving, demanding, striving, coercing. Individualizing; becoming separate from others and/or finding a personal path for expression. Physical expressions of passion and sexuality. Turn-ons, animal attraction, lust. The instinct for survival. Associations with and inclinations to violence, fighting and war. Adrenalin, testosterone, blood, muscles, movement. The nature of our impulses. Primitive states of being and reacting. Desire for freedom and independence. Traditional ideas of masculinity. Mars is the ruler of zodiac sign Aries, and was before the discovery of Pluto also said to rule Scorpio.
Planets aspecting Mars modify the distribution of energy within the individual, and add to the ways of expressing individuality. They affect "personality" in terms of spontaneous self-assertion, charismatic and dramatic energies. Mars aspects shape sexuality in its active, outreaching state, adding different dimensions of sexual behaviour and yearnings.