R. Yonah: Nadiv is one who gives according to his ability. He bestows Chesed and benefits his colleagues from the toil of his Nefesh and body. He seeks people's good. Many hope to him for help and benefit.

Orchos Tzadikim (Sha'ar ha'Nedivus DH v'Yesh): A person is honored via the Midah of generosity.

Malbim: Nadiv is one who gives according to what is proper, in a proper time and to a proper person, e.g. an Oni in need. A Nadiv does not have friends. The rich are not his friends, for he does not give to them gifts. However, many Aniyim who need him, they seek his face.

Rashi: All become friends [of an Ish Matan].

R. Yonah: All the praise [is for an Ish Matan]. This is like "Lamah Sari'i Re'a" (Michah 4:9) and "Ish Re'im Lehisro'e'a" (above, 18:24).

Rashi #1: It is one who gives Tzedakah.

Rashi #2: It is one who spreads Torah.

R. Yonah #1: It is one who gives great gifts amidst great wealth and generosity. Therefore, he gets a [good] reputation.

R. Yonah #2: Perhaps it is the same as Nadiv. The end of the verse repeats the beginning. It teaches the benefit from wealth and its highest level - Chesed and gifts. It is proper to toil to acquire wealth with this intent, if one will find desire of Chesed and generosity of the heart.

Malbim: He constantly scatters his money, also to Ashirim, amidst squandering. All are his friends, rich and poor. They join with him with comradeship, which depends on one's own benefit; it is not true friendship, like I explained above (refer to 19:4:1:4, 19:4:2:2).