What Is the Difference between Temptation and Sinful Thoughts?
To discern between sinful thoughts and temptation, it helps to understand that temptation itself is simply an offer of sin. When we are tempted, we face a choice between right and wrong.
When we are tempted and feel drawn to sin, it begins leading on a path toward sin in our actions, and we must guard our hearts in order to keep ourselves from continuing on that path. This is described in James 1:14-15: "But each one is tempted when he is drawn away by his own desires and enticed. Then, when desire has conceived, it gives birth to sin; and sin, when it is full-grown, brings forth death."
Since Jesus was tempted in all points as we are, yet without sin (Hebrews 4:15), He would have never tolerated a sinful thought. He would not have even considered sinning, but rather was firm in His resolve and immediately resisted sin by standing on the truth of God's Word (Matthew 4:10).
While it can be difficult to discern between temptation and sinful thoughts, the important thing is to take every thought captive (2 Corinthians 10:5) and immediately stop any thoughts from progressing or continuing in our minds.
This requires us to guard our hearts with all diligence (Proverbs 4:23).
Past sinful habits can still present themselves in our thoughts, and our immediate responses whether in thoughts, words, or actions may not be honoring to God, and it takes conscious effort to undo the effects of our past ways of thinking.
If we have used profanity in the past, it may be an instantaneous reaction without even being conscious of it in the moment. Immediate thoughts are different from being tempted (facing a choice) to use profane language.
With same sex attraction (as well as heterosexual lust), the thoughts must be stopped immediately. While the first thought of temptation is not an act of sin, the thoughts could become sinful if tolerated; consciously choosing to dwell on sinful thoughts is the same as acting on temptation in actions (Matthew 5:27-28).
Martin Luther wrote, "Thus you see that temptation can be avoided by no one; but resistance may be made and, with prayer and recourse to divine aid, we can put ourselves in readiness to meet such designs. In the book of an old father we read that a young brother expressed a desire to be rid of his thoughts. Thereupon the old father said: Dear brother, you cannot prevent the birds from flying in the air over your head, but you can prevent them from building a nest in your hair."
The more we meditate on truth and purity (Philippians 4:8), the less we will have to battle these thoughts; we are sanctified by truth (John 17:17).
The brain is designed to remember habits, and it can take time to undo undesirable habits, but it can be done with intentional effort in replacing wrong thoughts with pure thoughts.