Contradiction with Matthew 6:5
This verse teaches not to pray to be seen by others, whereas Romans 1:9 speaks about open mention of prayer.
Matthew 6:5: And when thou prayest, thou shalt not be as the hypocrites [are]: for they love to pray standing in the synagogues and in the corners of the streets, that they may be seen of men. Verily I say unto you, They have their reward.
Contradiction with Matthew 7:21
This verse implies that those who do the will of God, not just serve in spirit, will enter the kingdom of heaven, suggesting a more action-based faith.
Matthew 7:21: Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.
Contradiction with James 2:17
This verse suggests that faith without works is dead, while Romans 1:9 emphasizes serving with spirit.
James 2:17: Even so faith, if it hath not works, is dead, being alone. [alone: Gr. by itself]
Contradiction with 1 Samuel 16:7
This verse indicates that God looks at the heart, whereas Romans 1:9 seems to underscore serving in spirit in a way that might imply outward expressions.
1 Samuel 16:7: But the LORD said unto Samuel, Look not on his countenance, or on the height of his stature; because I have refused him: for [the LORD seeth] not as man seeth; for man looketh on the outward appearance, but the LORD looketh on the heart. [outward...: Heb. eyes]