C. F. Keil and Franz Delitzsch on Ecclesiastes 2:1

Ecc 2:1 “I have said in mine heart: Up then, I will prove thee with mirth, and enjoy thou the good! And, lo, this also is vain.” Speaking in the heart is not here merely, as at Ecc 1:16-17, speaking to the heart, but the words are formed into a direct address of the heart. The Targ. and Midrash obliterate this by interpreting as if the word were אנסּנּה, “I will try it” (Ecc 7:23). Jerome also, in rendering by vadam et affluam deliciis et fruar bonis, proceeds contrary to the usual reading of 'אן Niph. of נסך, vid., at Psa 2:6), as if this could mean, “I will pour over myself.” It is an address of the heart, and ב is, as at 1Ki 10:1, that of the means: I will try thee with mirth, to see whether thy hunger after satisfaction can be appeased with mirth. וּראה also is an address; Grätz sees here, contrary to the Gramm., an infin. continuing the בּשׂ; ūrēh, Job 10:15, is the connect. form of the particip. adj. rāěh; and if reēh could be the inf. after the forms naqqēh, hinnāqqēh, it would be the inf. absol., instead of which וּראות was to be expected. It is the imper.: See good, sinking thyself therein, i.e., enjoy a cheerful life. Elsewhere the author connects ראה less significantly with the accus. - obj., Ecc 5:17; Ecc 6:6; Ecc 2:24.

This was his intention; but this experiment also to find out the summum bonum proves itself a failure: he found a life of pleasure to be a hollow life; that also, viz., devotedness to mirth, was to him manifestly vanity.