They told David "Lo Savo Henah "Ki Im Hasircha ha'Ivrim veha'Pischim" (Shmuel II, 5:6). What does this mean?
'Rashi': They saw that they cannot stand in front of David. They put blind and lame people in front of the gate, to say 'David will not come here, unless he [first] fights these blind people.' They knew that it is disgraceful for David to fight them, so he will turn back and not fight them. This is why David offered a reward to whoever will fight them and divert them from there.
Radak (Shmuel II, 5:6, citing Targum Yonasan): Only when you remove the sinners and wicked who say 'David will not come here.'
Radak (Shmuel II, 5:6 citing Pirkei d'R. Eliezer 36): Anshei Yevus told Avraham, make a Bris with us that your seed will not dispossess the city of Yevusi, and we will sell to you Me'aras ha'Machpelah; he did so. Anshei Yevus made copper images 1 and erected them in the city square, and the Bris of the Shevu'ah was written on them. These are the images that "have eyes but do not see? feet, but do not walk" (Tehilim 115:5-7).
Radak (Shmuel II, 5:6 citing Ibn Ezra): If you turn to war, even the blind and lame will stop you from coming here. (They said so because) the tower was very strong; we do not fear you for war!
Ralbag (Shmuel II, 5:6): In the gate of the city were images of blind and lame [people]. They arranged that they lifted and moved heavy iron rods, so no one could approach. (Perhaps blind and lame people below helped to move them!) A stream came out of its mouth; the flow moved the images and sticks, just like flowing water makes a water mill turn. Malbim (ibid.) ? they 'say' that he cannot enter until he removes them.
Refer to Shmuel II, 5:6:6:1 and the notes there.
What is the relation between Metzudas Tziyon and Yerushalayim?
Mahari Kara, Radak (Shmuel II, 5:7): They are the same. Our verse says that David headed those who captured it; afterwards, it says how he did so.
R. Yeshayah (Shmuel II, 5:7): Metzudas Tziyon is the strongest, most fortified part of Yerushalayim.
Malbim (Shmuel II, 5:6,7): The Ivrim, Pischim and Tzinor were by the gate of Yerushalayim. The Metzudah (fortress) was on the other side of Yerushalayim. After conquering it, he requested someone to continue from that direction
Why was it called Ir David?
Abarvenel, Malbim (both in Shmuel II, 5:7): He himself captured it.
