In contrast to His assurance that they will one day sit on thrones, ruling over the tribes of Israel, Jesus warns Peter that Satan plans to trouble them severely. We lose a bit of subtlety in our English translation, because “sift you like wheat” is plural, but all of the “you” and “your“s in verse 32 are all singular. Jesus is telling him that while Satan will disturb them (and had to demand permission from God to do so), Peter will recover and give strength and encouragement to the rest of the disciples. Peter boasts that he will follow Jesus to prison and death, but Jesus responds that he will deny Him three times before dawn.
Next, Jesus contrasts the coming days with the times He sent them out to preach the Good News. Before, they took no provisions, tools, or extra clothes for the journey, but relied on the hospitality of strangers. Now they are to make preparations: get your moneybag, a bag to carry things, and even a sword to protect themselves. I emphasize self-defence because Jesus never calls on His followers to attack anyone. All of these items together indicate the hardships the disciples are going to face once Jesus is handed over to the authorities. The disciples show Jesus that they have two swords already, which feels a bit like finding out that the super-nice, extra-humble guy at work goes to the gun range on the regular.
You are sovereign over all the evil forces that oppose You, and we can trust in Your provision both now and forever.