WARNING: The following contains spoilers for The Amazing Spider-Man #51 by Nick Spencer, Patrick Gleason, Edgar Delgado & VC's Joe Caramagna, on sale now.
Spider-Man knows he is in a battle for his soul against the demonic Kindred, so he went to the man who knows demonic entities best, Doctor Strange. However, Spider-Man also knew he needed to have a backup plan because he is the only one who can win this battle. For that reason, he also went to Black Cat in Amazing Spider-Man #50.
Spider-Man knew that Doctor Strange had a way to help him because the two had been in a very similar situation before. However, Spider-Man also knew that there was a chance Strange wouldn't trust him with the task at hand. Much to his surprise, Strange did trust him, and Spider-Man ended up making the Sorcerer Supreme regret his trust by betraying him. He had Black Cat sneak into the Sanctum Sanctorum and steal a magical device to use in battle.
From the moment Spider-Man showed up at the Sanctum Sanctorum in Amazing Spider-Man #50, he has done nothing but withhold facts from the Sorcerer Supreme. He only told Doctor Strange what he needed to know to get him into the Sanctum Sanctorum. Spidey told Strange about the possessed members of the Web-Totem when Silk attacked at the end of the issue, but Strange has now learned Spider-Man withheld more from him, possibly for years. When Strange tried to trust Peter with the Hand of Vishanti, he realized something had changed since the last time Spider-Man used it.
Whether or not Spider-Man knew this was coming into play or not, he had a backup plan if Doctor Strange kicked him out without the help he needed. It turns out Peter had every right to be leery because Strange did end up kicking him out after realizing that Spider-Man had done something that affected his use of the Hand of Vishanti -- and likely anything else that dealt with what was in Peter's soul. This was possibly the entire "One More Day" storyline where Peter made a deal with the devil. Doctor Strange was right to try to keep it from Spider-Man because as soon as Peter went into the astral plane, he saw a vision of Mary Jane and realized too late that he walked into a trap set by Kindred.
Spider-Man got the Hand of Vishanti by double-crossing Doctor Strange. Stephen agreed to help Peter, and he agreed to let him be the one who faces Kindred. Strange knew that Madame Web was the answer thanks to the Web of Life and Destiny connecting them. Since Peter and Madame Web share the Totem, Peter can access this through the astral plane, and the way to get there is the Hand of Vishanti. However, when Strange realized Peter did something he shouldn't have, he blew him out of the Sanctum Sanctorum and set out to find a way to save the day on his own. The problem is the Hand of Vishanti was now gone.
After Spider-Man took a beating from his possessed friends, he made one stop before he went to the Sanctum Sanctorum: Felicia Hardy's house. While Doctor Strange was dismissing Spider-Man, she snuck in and stole the Hand of Vishanti. She also recorded Doctor Strange's incantation and played it back while Spider-Man prepared to enter the astral plane. Sadly, it turned out to be a trap, and now Spider-Man and Kindred are ready to battle. This also might not be the best thing for Black Cat since the Spider-Totem can track Peter, and he just pulled one of his oldest allies into a fight with a seemingly unstoppable demon.