SB 10.60.15
yayor atma-samam vittam
janmaisvaryakrtir bhavah
tayor vivaho maitri ca
nottamadhamayoh kvacit
Translation:
Marriage and friendship are proper between two people who are equal in terms of their wealth, birth, influence, physical appearance and capacity for good progeny, but never between a superior and an inferior.
Purport:
Persons of superior and inferior qualities may live together in a relationship of master and servant or teacher and student, but marriage and friendship are proper only between those of equal status. The word bhava, in the context of marriage, indicates that a couple should have a similar capacity to produce good offspring.
Lord Krsna here presents Himself as materially unqualified. In fact, the Lord does not have any material qualities: He lives in pure spiritual existence. Thus all the Lord’s opulences are eternal and not of the flimsy mundane sort.