Moral Decisions

What if we are not sure of what is right or wrong in a particular situation? Saint John says that sin is lawlessness.  God's law defines sin.  I find the Westminster Larger Catechism  list of what the law commands and forbids very instructive.  It is a careful study of scripture. For example, do you think of  "undue delay of marriage" as a violation of the seventh commandment?  It is. Many of life's decisions would be clearer if we were better students of the word.