Tal por tal, like for like, or "One good turn deserves another." If this has in all ages been esteemed a duty, in our commerce with persons who are indifferent to us, we are in a particular manner called upon to observe it, in our conduct to our parents, and to make the best return in our power, for their care in nourishing and supporting us in our infancy; for imbuing our minds with good principles; for cultivating and improving our understandings, and thereby enabling us to support ourselves in a mature age, and to fill with credit that rank, or situation in life, in which we may happen to be placed.You can read more commentary by Bland online, and here is more about Bland's book. The image comes from the Cheezburger.com site. The poster is generated with AutoMotivator. Here is a full-sized view of the poster.