1 Corinthians 15:58 Therefore, my beloved brothers, be steadfast, immovable, always abounding in the work of the Lord, knowing that in the Lord your labor is not in vain.
Did you know a man can be faithful to his wife for twenty years and be disloyal to her the entire time?
For the duration of those years together if that man never has intercourse with another woman, he would have been a faithful husband. If however he lusts and lurks after every woman he sees other than his wife then he would have been disloyal to her the entire time.
The same thing applies to us and our relationship with God. We can be faithful to Him by praying regularly and attending church, however we can be disloyal if at every chance we get we entertain sin. In the verse above steadfastness speaks to our loyalty to God. We are expected as believers to be both faithful and loyal to God in everything we do. Being one without the other just isn’t enough when it comes to serving Jesus.