'Lower' in the Bible

You however, brethren, were called to freedom. Only do not turn your freedom into an excuse for giving way to your lower natures; but become bondservants to one another in a spirit of love.

This then is what I mean. Let your lives be guided by the Spirit, and then you will certainly not indulge the cravings of your lower natures.

For the cravings of the lower nature are opposed to those of the Spirit, and the cravings of the Spirit are opposed to those of the lower nature; because these are antagonistic to each other, so that you cannot do everything to which you are inclined.

Now you know full well the doings of our lower natures. Fornication, impurity, indecency, idol-worship, sorcery;

Against such things as these there is no law. Now those who belong to Christ Jesus have crucified their lower nature with its passions and appetites.

He who sows in the field of his lower nature, will from that nature reap destruction; but he who sows to serve the Spirit will from the Spirit reap the Life of the Ages.