R. Yonah: This is the fourth attribute - to toil for Chachmah the way that one toils for money. Chazal said, in order to grow wise, one should (a) request Chachmah from its owner -- "Ki Hashem Yiten Chachmah mi'Piv Da'as u'Sevunah" (6), and (b) spend much time learning and minimize business. Without both of these, he will not merit Chachmah (Nidah 70b).

Malbim: One seeks money via business - he profits via his merchandise or his hands' work. This is a Mashal for seeking Chachmah - he switches and gives all worldly desires for the sake of Chachmah.

Chafetz Chaim (Toras ha'Bayis 11): One must love it like one who loves money, to be pained over its loss and rejoice in attaining it.

Avi ha'Ezri (Nezikin, first edition, introduction): This is the Shi'ur of constant exertion and toil.

R. Yonah: The fifth attribute is that Chachmah be pleasure to his Nefesh, and his engagement in it not be a toil to him amidst great love, like it says "v'Hayu v'Einav k'Yamim Achadim b'Ahavaso Osah" (Bereishis 29:20). If people told a man that there is a treasure in this house or in this valley, searching for it will not be a burden to him, since he knows that he will find great wealth in one place and become rich in a moment. One must toil for Chachmah like one who seeks money via different labors and businesses, and to attain with toil and seeking it, the delight of seeking treasure - "Sas Anochi Al Imrasecha k'Motzei Shalal Rav" (Tehilim 119:162). According to the delight in the toil and searching, the eyes of his Sechel will be opened, and it will be guarded in man's heart - "Nachalasi Edosecha l'Olam Ki Seson Libi Hemah" (ibid. 111). A person learns Torah only where (i.e. the topic that) he desires (Avodah Zarah 19a). Success in Torah depends on desire!

Malbim: One seeks treasure via digging deep into the land or the depths of the sea. This is a Mashal for exerting to delve into deep matters of Chachmah, to take out pearls hidden in the depths and secrets of Torah and wisdom.