Evangelicals are taught that God the Father, Jesus the Son, and the Holy Spirit are the Perfect Trinity, the One being them as part of God.
During the Old Testament before Jesus's birth, only the Jews could commune with God as His people. They did this by going to the synagogue but only the most devout Rabbis were allowed in the Holy area inside.
When Jesus came, born as our Saviour, the Jews rejected him as the Messiah. They are still awaiting his first coming. They still follow the Old Testament rituals because the Saviour hasn't yet arrived for them.
Where the Gentiles , us, are awaiting the second coming and follow Jesus's teachings of the New Testament.
At the time of Jesus's death on the cross it went dark and there was a great shaking of the ground (earthquake) and the Veil in the temple that separated the rabbis was ripped in two. Due to the Jews rejection of Jesus as the Saviour, the Gentiles were given the chance to become Christ believers.
Our non-Jewish blood means we do not live under the Jewish law of the Old Testament. Jesus taught us how to pray in the model of the Lord's Prayer Prayer. And he taught the disciples who taught us "No man cometh to the Father except through me."
You can pray to God, He wants to hear from you, but if you are making a petition or request, you close your prayer with, "In Jesus Christ's name, Amen.
Hope that helps answer your question.