What is the meaning of "Avi"?
Radak citing Targum Yonasan: My master.
Metzudas Tziyon #1: A great person or officer (above me), like a father over his son.
Metzudas Tziyon #2: Since he was his father-in-law, it is as if he was his father.
Torah ha'Temimah: You are like my father, and you would not kill me (we assume that a thief tunneling into a house intends to kill the owner if he will confront him, unless the owner is his son). 1
Perhaps he means that David merely said so to try to arouse Sha'ul's love. Sha'ul twice threw a spear at him to kill him! However, in this very verse, David said 'you ambush me to kill me'! This requires investigation. (PF)
Why did he say "see" twice?
Rashi: Put your heart to the matter (see intellectually), and see the evidence - the corner of your robe in my hand. I could have killed you!
What was the testimony of the corner?
Malbim: This shows that I was close to you, and I had a sword in my hand, and I was not so afraid that I could not act. 1
What is the meaning of "Tzodeh"?
Radak citing Targum Yonasan: You wait in ambush.