Where does it say, in the Bible, and that by his stripes we are healed?

Your question refers to 1 Peter 2:24 –  “Who Himself bore our sins in His own body on the tree, that we, having died to sins, might live for righteousness – by whose stripes you were healed.”  This healing is not a physical healing now, in this lifetime.  Instead, it is the healing that we received when we accepted Jesus as our savior – this healing is the forgiveness and covering of our sins by Jesus’ death on the cross.  Based on the context of this chapter in 1 Peter, the Apostle Peter is addressing the Church – also known as the believers in Jesus. This healing is then the atonement for sins we receive now when we believe and dedicate our lives to serve God and Jesus.

We know that Jesus has a mission to heal the church and the whole world. Jesus will bring sight to those that are blind – bringing the willing into a perfect moral condition with the correct and accurate view of the truth. (“…I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people. And they shall teach no more every man his neighbor…saying, Know the LORD: for they shall all know me, from the least of them unto the greatest of them…” Jere 31:34) Our Lord read a prophecy about himself to the congregation on the Sabbath saying, “The Spirit of the Lord is upon me, because he hath anointed me to preach the gospel to the poor; he hath sent me to heal the brokenhearted, to preach deliverance to the captives, and recovering of sight to the blind, to set at liberty them that are bruised” (Luke 4:18).  Jesus did perform miracles of healing but that was not the complete fulfillment of these scriptures. 

Jesus will have a greater healing work that will be accomplished for the whole world.  His miracles of healing, while he was on Earth, were just a picture and an example of what would be accomplished in his kingdom. Christ’s healing sacrifice has two parts.  First, his death is applied as atonement for the church and subsequently for the whole world. All will have their sins erased (“…for I will forgive their iniquity, and I will remember their sin no more.” Jere. 31:34) and the sentence of death removed.  We see this in 1 John 2:2: “He is an atoning sacrifice for our sins, and not for ours only, but also for the sins of the whole world.”  Then, the rest of the world will be brought back to moral and physical perfection in Christ’s kingdom (Rev 22:1-2).