"...the LORD had regard for Abel and his offering, but for Cain and his offering he had no regard. So Cain was very angry..." (Gen 4:4b-5a. ESV)
The oldest profession isn't what you think.
Nowadays when we use the term "professional" we mean someone who takes pride in their work and performs their duties responsibly. A plumber who shows up to the job site intoxicated is charged with "acting unprofessional". We apply this word to lawyers, electricians, teachers, and fast food managers--and just about any other job. For hundreds of years, however, the word 'professional' was only used for three occupations: medicine, law, and ministry. Our English word comes from the Latin term professio, which means a public declaration with the force of a promise. The oath to which the three great professions subscribed was viewed as larger then themselves--it was a life long mission which they were duty bound to perform no matter the circumstance they found themselves in.
Yet the term has an even older meaning. Some joke that the oldest profession is prostitution--but there is a profession (and a sin) that is much older than that. One of the first professions, or public oaths, was taken by Cain. In fact, two professions were made. One by Cain and the other by his brother, Abel. Abel made a profession of faith to God and publicly swore an oath to serve and obey Him. Cain made the same profession and took the same oath.
The difference is that only one meant it. Abel was willing to give God his heart and do whatever his Lord asked. Cain was only willing to publicly profess allegiance. On the outside he looked like he was fulfilling his promise to God, but on the inside he was only loyal to the oath to himself. Cain was the very first legalist recorded in the Bible. He was willing to serve God, but it had to be on Cain's terms. Faith is giving our hearts to God; legalism is given everything to God but our hearts.
Legalism is one of the oldest professions known to man. Over the years humanity has become quite the expert.
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