Ruth 1:16 (NASB) says:
But Ruth said, “Do not urge me to leave you or turn back from following you; for where you go, I will go, and where you lodge, I will lodge. Your people shall be my people, and your God, my God.
Ask yourself: was it love for and loyalty to, the God of Israel, that motivated Ruth to go with Naomi; or was it love for and loyalty to, Naomi herself? "where you go", "where you lodge", "your people", "your God". Ruth was essentially saying: "I love you so much, mother, that I will loyally accept anything you accept. I will make your life my life. What you love I will love". What if Naomi had decided to become a Baal worshiper? "your God [shall be] my God"! Yes, Ruth would have followed suit. Really, it is clear that Ruth loved Naomi more than she loved Jehovah. She became a worshiper of Jehovah only because Naomi was one!
Contrast Ruth's attitude with the attitude Jesus urged his followers to have, as recorded at Matthew 10:37 (NASB):
“ He who loves father or mother more than Me is not worthy of Me; and he who loves son or daughter more than Me is not worthy of Me."
Jesus urged the opposite. He said we should have greater affection for him than for family. Ruth is not worthy of Christ, because she put her mother in law ahead of everything else - including God. Her choice of worship was predicated on being with her mother in law.
Isn't it ironic that Ruth became the ancestress of Jesus because of her having exactly the kind of attitude that Jesus told his followers they should not have?