Say before the Lord; i.e. address him as present and ready to hear. The expression, "before the Lord," does not necessarily imply that it was in the sanctuary that the prayer was to be offered. Isaac proposed to bless his son "before the Lord," i.
e. within his own house or tent (Genesis 27:7); and so the Israelite here might in his own home make his prayer to the Omnipresent Jehovah. I have not transgressed thy commandments, etc. This is not a self-righteous boast; it is rather a solemn profession of attention to duties which might have been neglected, and refers, not to the keeping of every commandment, but to the having faithfully done all that the Law required in respect of tithes.