The Cross: It is what Satan hates most, because it represents his ultimate defeat. The Cross stands for the Finished Work, which Christ Himself completed at Calvary. Therefore, more than anything, Satan tries to make Christians avoid the Cross through his tool-temptation.
The devil tried to tempt Jesus repeatedly, working to get the Son of God to venture outside of the will of the Father in His humanity. Jesus had to make it to the Cross in order to win the victory. Satan, knowing that, did everything in his power to keep Jesus from it.
The Cross is the door to resurrection life. It is where Jesus conquered death and removed its sting. The grave can no longer claim victory, and we no longer have to live in fear, even of death.