To God’s elect, exiles scattered throughout the provinces of Pontus, Galatia, Cappadocia, Asia and Bithynia, who have been chosen according to the foreknowledge of God the Father, through the sanctifying work of the Spirit, to be obedient to Jesus Christ and sprinkled with his blood: Grace and peace be yours in abundance.
"Chosen by foreknowledge" is a form of selection that does not violate our free will. We choose to accept the love of God, he sees our choices in the future, and on that foreknowledge He elects us. It makes perfectly sense, once we accept that God is not bound by time and space like we are.
When we decide and do, the trinity decide and do. However, God has the privilege of deciding and doing in the past and in the future, whereas the only place and time we have available to us is here and now. The timelessness only available to God explains our past. God decided to do things for us in the past that has to do with our choices in the future. It becomes a little complicated, and Peter simply call us "God's elect". The sanctification of the Spirit and the sacrifice of Christ is both past and future for us. It has already happened and is 100% by grace, but it will continue to happen for or with us as we let it happen to us.
How do I live with God's foreknowledge?