The Bible is the inspired Word of God (2 Timothy 3:16,17), and is the final authority in all matters.
The forgiveness of sin is provided to all who will repent and receive Jesus as their own personal Savior (Acts 10:43 and 17:30).
"Speaking in other tongues" is the initial evidence of the infilling of the Holy Spirit (Acts 10:45 and 11:17).
The Holy Spirit empowers us to manifest the Fruit of the Spirit, as listed in Galatians 5:22, and the ability to manifest the Gifts of the Spirit, as listed in 1 Corinthians 12:8-10.
The 5-fold ministry as is listed in Ephesians 4:11.
Because God made us in His image, a 3-part being consisting of Spirit, Soul, and Body, He deals with us in all 3 parts (1 Thessalonians 5:23).
The words we speak are very important. Life and death are in the power of the tongue (our words) as stated in Proverbs 18:21. Our words must be in line with God's Word: speaking what God has said about us and others – what we have and who we are in Christ (Matthew 12:36,37 and 2 Timothy 4:18).
The Lord Jesus Christ is returning, as written in Acts 1:11, for the catching up of His body, the Church, and that this catching up (the Rapture) will occur before the Great Tribulation Period lasting 7 years.
After the Tribulation, Jesus will physically return and stand on the Mount of Olives (Zechariah 14:4), after which will come the 1000 year reign of Christ and the Church over the Earth as described in Revelation, chapter 20.
There is a literal Devil, Satan, who is now functioning with the power and authority he took from the first Man, Adam, causing him to fall, as seen in Genesis, chapter 3. Satan has a kingdom of other fallen angels, called demons, who followed him in his rebellion in Heaven. Also under his authority are those men and women who are obedient to him and not to Jesus (John 8:44 and 1 John 3:8).