C. F. Keil and Franz Delitzsch on Deuteronomy 26:12-13

Deu 26:12-13

The delivery of the tithes, like the presentation of the first-fruits, was also to be sanctified by prayer before the Lord. It is true that only a prayer after taking the second tithe in the third year is commanded here; but that is simply because this tithe was appropriated everywhere throughout the land to festal meals for the poor and destitute (Deu 14:28), when prayer before the Lord would not follow per analogiam from the previous injunction concerning the presentation of first-fruits, as it would in the case of the tithes with which sacrificial meals were prepared at the sanctuary (Deu 14:22.). לעשׂר is the infinitive Hiphil for להעשׂר, as in Neh 10:39 (on this form, vid., Ges. §53, 3 Anm. 2 and 7, and Ew. §131, b. and 244, b.). “Saying before the Lord” does not denote prayer in the sanctuary (at the tabernacle), but, as in Gen 27:7, simply prayer before God the omnipresent One, who is enthroned in heaven (Deu 26:15), and blesses His people from above from His holy habitation. The declaration of having fulfilled the commandments of God refers primarily to the directions concerning the tithes, and was such a rendering of an account as springs from the consciousness that a man very easily transgresses the commandments of God, and has nothing in common with the blindness of pharisaic self-righteousness “I have cleaned out the holy out of my house:” the holy is that which is sanctified to God, that which belongs to the Lord and His servants, as in Lev 21:22. בּער signifies not only to remove, but to clean out, wipe out. That which was sanctified to God appeared as a debt, which was to be wiped out of a man’s house (Schultz).