Q1. (1:18) In what sense are we given spiritual birth by the "word of truth"? What does spiritual life have to do with the Word?
Jesus said, that when He would have to go back the Heavenly Father, He would not leave us alone on this earth to do battle with Satan by ourselves. Jesus said that He would send us a helper, the Holy Spirit of God.
When we accepted the word of truth, that being Jesus ("the Word") we became reborn. Just like Jesus told Nicodemus, that he (Nicodemus) would have to be reborn of water and spirit. That happened at our baptism. The Spirit of God was sealed in us forever.
Our spiritual life grows as we here God's word. And as the Holy Spirit in us helps us to understand God's word. The Holy Spirit will also guide us as we hear God's word to live by God's word.
1Peter 2:2-5 says this: "Like newborn babies, crave pure spiritual milk, so that by it you may grow up in your salvation, now that you have tasted that the Lord is good. As you come to him, the living Stone---rejected by men but chosen by God and precious to Him---you also, like living stones, are being built into a spiritual house to be a holy priesthood, offering spiritual sacrifices acceptable to God through Jesus Christ." NIV
Our spiritual life is being fed daily with God's word, through reading it, hearing it, and living it. We grow spiritually strong with each passing day until the day that Christ will return.
Grace and peace to all.