Consider James 1 speaking of how our faith is tested.
James 1:2-4
My brethren, count it all joy when you fall into various trials, knowing that the testing of your faith produces patience. But let patience have its perfect work, that you may be perfect and complete, lacking nothing.
James 1:12
Blessed is the man who endures temptation; for when he has been approved, he will receive the crown of life which the Lord has promised to those who love Him.
What temptations are there?
The most common that scripture often warns about is the lust of the flesh in turning back to righteousness by works of the law/fornication with Hagar.
James 1:22-25
But be doers of the word (believing in Jesus), and not hearers only, deceiving yourselves. For if anyone is a hearer of the word and not a doer, he is like a man observing his natural face in a mirror; for he observes himself, goes away, and immediately forgets what kind of man he was. But he who looks into the perfect law of liberty and continues in it, and is not a forgetful hearer but a doer of the work (believing in Jesus, john 6:29), this one will be blessed in what he does.
Those who are forgetful hearers are those who forget that in Christ they are righteous (Rom 4:5) and they instead turn back to the law to determine righteousness by works of the law.
The sin the world is convicted of is unbelief in Jesus, John 16:9.
Those under the law are in unbelief.