From where did Hashem take Adam, before placing him in Gan Eden?
Targum Yonasan: Hashem took Adam (He convinced him with nice words - Rashi) from Har Hamoriyah (the location of the Beis-Hamikdash) where He had created him.
What does "leAvdah ule'Shamrah" mean?
Targum Onkelus: To work in the garden and to look after it.
Targum Yonasan: To study Torah and to keep Mitzvos.
Ramban #1 (in Pasuk 8): To plant wheat, vegetables or spices, and to harvest it at will (since it grew as soon as it was planted), and to pick fruit and eat it as he pleased.
Ramban #2 (Chapter 3, Pasuk 22, citing Medrash]): To bring Korbanos.
Seforno #1: To serve his Nishmas Chayim and to preserve his moist in his body from dissipating (presumably by eating the fruits in the garden.
Seforno #2: In Pasuk 8, the Seforno also explained that Hashem placed Adam in the garden 'to receive the Tzelem Elokim and to indulge in spiritual matters via the garden's air and its food.
Why does the Torah refer to the garden in the feminine ("le'Avdah u'le'Shamrah")?
Ramban (citing the Midrash Rabah): "le'Avda u'le'Shamrah" refers to bringing Korbanos. And the special blessings of Gan Eden depend upon the influence of the celestial powers, which in turn, are activated by the Korbanos brought by man.
רש"י: לקחו בדברים נאים: מנין לפרש כך?
גור אריה: עיקר האדם הוא הדעת שבו, ואת הדעת אין לקחת אלא בדברים.
רש"י: פיתהו להיכנס: מה פרוש הדברים?
גור אריה: הכוונה שלא לקחו נגד רצונו אלא אמר לו שזהו גן עדן.