The average believer would never consider the word joy to be an appropriate descriptive term for temptations. There is a great explanation for this as the average believer experiences little to no victory when tempted. Temptations put a man’s faith on trial. When his faith stands the test, he learns patience. Therefore, he sees temptation as a means by which he can grow in the Lord and add virtues such as patience. It is not that he finds joy in the temptation itself, but that God can and will use that temptation to make him "perfect and entire, wanting nothing" (James 1:4). Believers who fight through and obtain victory find joy in knowing that their faith pleases God (Hebrews 11:6).
Discerning the difference between the workings of God and the mischief of Satan sometimes serves as a difficult task for believers. Although the Devil is called the tempter in Matthew 4:3 and 1 Thessalonians 3:5, the Bible also shows that God uses temptation to try a man (Genesis 22:1). Other than the association to instigating temptation, God and Satan have no other common ground in this matter. The Devil’s motive and method of temptation is simply wicked. On the other hand, the Lord tempts only for the sake of trying one’s faith to bring about a righteous outcome. Do not discount the fact that God never tempted anyone with evil (James 1:13).
Our passage tells us that God is not in all the thoughts of the wicked (Psalm 10:4). It also points out that the thoughts of the wicked “are thoughts of iniquity” (Isaiah 59:7). Obviously, the wicked despise the Lord in their thoughts, but the Lord also despises the thoughts of the wicked. This is why we are told that “The thoughts of the wicked are an abomination to the LORD” (Proverbs 15:26). King David, whom God called “a man after mine own heart” (Acts 13:22), added that the thoughts of the wicked were against him for evil (Psalm 56:5). These wicked thoughts are based upon pride (Psalm 10:4). Conversely, a man yielded to the Lord desires to bring “into captivity every thought to the obedience of Christ” (2 Corinthians 10:5).
If asked concerning the origin of thoughts, the average person would swiftly respond with “the mind” or some similar answer. This is not, however, the emphasis of scripture. Overwhelmingly, scripture indicates that thoughts proceed from the heart. This does not mean the beating organ within one’s chest since the scriptures use “heart” in a different manner. When God brought judgment in the days of Noah, He saw that the thoughts of man’s “heart was only evil continually” (Genesis 6:5). In Matthew 15:19, the Bible says, “For out of the heart proceed evil thoughts.” In Luke 24:38, the Lord Jesus asked the disciples, “why do thoughts arise in your hearts?” When one’s thoughts are not according to God’s will, it is a matter of the heart not being right with God.