Line 3. Gong is the highest one of the 5 titles of nobility in Zhou time. See hex.6. The character for sacrificing is the
same one as 'expansion'.
Line 5. Fu, "truth" is most of all the confidence one inspires in others. See Harmen's article. 14.5: He inspires confidence which connects and creates reverence: the quality of fu enables the king to connect with his people and make them stand in awe with respect and trust.