Here; his conception was not in holiness, but his birth was in holiness - כאן שהורתו שלא בקדושה ולידתו בקדושה
According to רש"י if one returns a loan to the בן הגר who was הורתו שלא בקדושה ולידתו בקדושה then רוח חכמים נוחה הימנו , however if he was הורתו ולידתו שלא בקדושה, then אין רוח חכמים נוחה הימנו. The ר"י maintains the exact opposite; since by לידתו בקדושה, we may mistakenly assume that he is a ישראל גמור.
Here it is by one robbery; here it is by two robberies - כאן בגניבה אחת כאן בשתי גניבות
According to רש"י; רבא maintains that if he stole only once he is not resold, but he is sold twice if he stole twice. However אביי maintains that for one העמדה בדין you are sold twice, however if he stole from two people he is only sold once.
According to תוספות; רבא maintains that if he stole once he is resold, if he sold twice he is only sold for the first גניבה. However אביי maintains that he is resold for the same person even for two גניבות, but he is not resold if he stole from two people .