Note 7 at Gal. 6:5: This verse is the exact opposite of verse 2 but it makes Paul's point perfectly. In verse 2, Paul said, "Bear ye one another's burdens." Verses 3-4 stripped away any objections that someone might have to doing that. Then here, he gives the clinching argument, "For every man shall bear his own burden."

His reasoning is that since all of us have burdens that we bear ourselves, we ought to be quick to help others with their burdens. We reap what we sow (v. 7) and God doesn't extend mercy to those who have shown no mercy (Jas. 2:13). Therefore, those who don't help others will not be helped. We don't want that. So, help others and sow a seed for your own future needs.