2 Grace to you and peace from God our Father and the Lord Jesus Christ.
Grace — The Galatians (Galatians 1:3) were legalistic (too hard) — grace is the cure. The Corinthians (1 Corinthians 1:3) were too carnal (too easy) — grace is the cure.
Romans 15:26 — ministering to Israel — poor saints
If Ephesians 1:3 is true (that God blesses us spiritually), it is our duty to minister to Him in physical things, speak well of Him before others, in personal devotions.
God — He is the Father of the Son, and also the God. He was Judge on the cross. My God, why hast Thou forsaken Me? (Mark 15:34)
John 20:17 — the only other place Jesus calls His Father “God”