True thankfulness is accompanied by true obedience in today's passage.  There is no diminishing of standards for an offering of thanksgiving compared with any other offering.  This sacrifice was to be given whole heartedly by the Israelites.  In fact if they were to let standards slip in any way in this offering it might‘not be accepted’,  the bringer might still ‘bear his iniquity’ (v.18.), and further still an Israelite might have been ‘cut off from his people’(v.20.). The passage teaches us the joy and the importance of bringing to God our thanksgiving, which we should offer up just as fervently as our prayers of petition for others, and our prayers for forgiveness for ourselves.  His goodness, His faithfulness, and His provision is what gives us confidence in all other things, and before all other things we should give Him thanks for this.   Let's pray that in the details of our everyday lives, we would be just as diligent in our thanksgiving as the Israelites were required to be in their offering.