Do not put yourself forward in the king's presence or stand in the place of the great; for it is better to be told, "Come up here," than to be put lower in the presence of a noble."
This advice dealt with more than etiquette. It, like other proverbs, was intended to help young people learn how to advance at court, and how to avoid embarrassing oneself on the way up.
When Jesus was speaking to the guests at the wedding banquet, the advice he gave was very similar, but he also spelled out the negative consequences, "When you're invited to a wedding banquet, don't seat yourself at the place of honor because somebody more distinguished may show up later and you'll be asked to move."
In his allusion to the proverbs, an allusion that his first hearers would have recognized, Jesus is reminding them that we do not have control over our perceived status, that we do not have the ability in ourselves to make ourselves exalted. But, we do have the ability to debase ourselves from time to time.
In the Proverbs, the actual king, and in Luke, the metaphorical host decide who gets what place at the table.
In his commentary of the Luke passage in the August 24, 2010, issue of the Christian Century, Patrick Wilson writes:
Who is this host who speaks so graciously to us and calls us friend? Who can it be other than Christ himself? We do not have to scramble for a place at his table. Our names are on the invitation list. A place is prepared, and when we hold back, uncertain that we really belong, too timid to believe we are truly welcome, he says, "Friend, come up higher."
Everyone is welcome here. You don't have to puff yourself up or pretend. Your value is not determined by calculations. You don't have to get and grab and grasp and grapple for a place. You are welcome here.