The devil is very powerful, and we must never underestimate either his power or his capacity for great evil. The Bible calls him our adversary, and compares him to "a roaring lion" - the strongest of all the animals - "looking for someone to devour" (1 Peter 5:8).
But the devil isn't all-powerful; that distinction belongs only to God. When Jesus Christ came into the world, the devil did everything he could to stop Him and keep Him from fulfilling His divinely-appointed mission to bring us salvation. And at times it looked like he might be successful, for the authorities turned against Jesus and finally put Him to death on the cross. How the courts of Hell must have rejoiced when Jesus drew His last breath!
But that wasn't the end! Three days later, the tomb was empty, and Jesus Christ had been raised from the dead. Death and Hell and Satan had been conquered by the power of God! Jesus, the Bible says, "was declared with power to be the Son of God by his resurrection from the dead" (Romans 1:4). And some day, the final battle will be fought, Satan will be conquered, and we will be safely in God's presence forever.
In the meantime, don't try to fight Satan's temptations in your own strength. Instead, open your heart and life to Jesus Christ, and turn to Him every day for the power you need to resist temptation and do what is right.