Devote – Dedicate by a vow or solemn promise.
Devotion – Profound religious emotion of awe and reverence; A strong attachment to, or affection for a cause, person, religion, etc., marked by dedicated loyalty.
Devoted is the past participle of Devote, and you can devote anything you want to anyone you choose; it need not be only to God. When you take a vow, you are devoted
God used this word in its various forms 9 times in Scripture: 8 times to Israel in their Masoretic Text Old Testament, and once to the Body of Christ in the transition book of Acts.
When God used ‘Devotion’ in the book of Acts, God is addressing the vanity of religion; among others, Christianity and Judaism are religions.
In the 1400s, the Catholic Church (Christianity) introduced the intransitive verb “Devotion – An act of religious worship; A religious exercise; Piety”.
Today, most Christian have, or do, their “devotionals”; wherein they spend time learning their ‘church doctrine’. They like to call it studying the bible, but the material most used in their devotions are religious commentaries, not Scripture. It is true that they are devoted, but their devotion is to their religion, not God.
See also Christian, Consecrate, Dedicate, Devout, Doctrine, Jew, Sanctify, Study, Vanity