"The LORD our God is One", The Father of those who know Him. He is known in three persons (Father, Son and Holy Spirit).
Man (though created righteous) disobeyed God and is sinful and unholy before God. Unable to earn by deeds a right standing with God and is under His eternal, yet just, judgement.
Jesus Christ is "God with us" in the flesh, the promised & prophesied Messiah of Israel; The Saviour. Born of a virgin yet fully divine; taking on flesh, yet without sin.
All are commanded, therefore, to quickly repent and to simply believe in Him for everlasting life.
By God's Holy Spirit, God is always with His children. He helps us in our weakness as we walk with God and pray, bearing the fruits of God's holiness in our lives (love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self control).
The Bible is God's Word. It is Living through the Spirit of God, for by it He speaks to us. As it is God's Word, it is the infallible foundation for all we can "know" as fallible humans.
Sinners can be justified (proclaimed holy) by God & reconciled (re-united) to God, solely by the Grace of God, through the gift of Faith in Jesus Christ. It is nothing of us and we cannot boast.