Seeing as the Kohen has immersed in a Mikvah, why does the Torah write "u'Va ha'Shemesh ve'Taher"?
Rashi (in Sotah, 29b): To teach us that, in spite of the Tevilah, 1 until nightfall he is still Tamei (and has the Din of a Sheini).
Which allows him to eat Ma'aser.
What does "min" come to exclude?
Why does the Torah add "Ki Lachmo hu"?
Seforno: It is precisely because Terumah is the Kohen's staple diet that he is permitted to eat it already at nightfall and does not need to wait until he brings his Korban the next day. 1
This verse teaches that he is Tahor at night. Verse 6 implies that right after immersing, he may eat Kodshim!?
Moshav Zekenim (from Yevamos 74b): Once he immerses, he may eat Ma'aser. He is Tahor for Terumah only at night.