Rule Regarding Passages of Scripture in Which Approval is Expressed of Actions Which are Now Condemned by Good Men
32 Therefore, although all, or nearly all, the transactions recorded in the Old Testament are to be taken not literally only, but figuratively as well, nevertheless even in the case of those which the reader has taken literally, and which, though the authors of them are praised, are repugnant to the habits of the good men who since our Lord's advent are the custodians of the divine commands, let him refer the figure to its interpretation, but let him not transfer the act to his habits of life. For many things which were done as duties at that time, cannot now be done except through lust.
Source: Christian Doctrine (New Advent)