The Sufficiency of Christ
Jesus Christ is completely adequate for all of salvation and all of life.
Christ is 'the way and the truth and the life'—sufficient for salvation, sanctification, and glorification. 'In Christ all the fullness of the Deity lives in bodily form, and in Christ you have been brought to fullness.' Nothing needs to be added to Christ; everything needed is found in Him. This sufficiency addresses both religious additions (rituals, rules) and secular substitutes (success, relationships). Acknowledging Christ's sufficiency brings rest from striving and confidence in facing life's challenges. He is enough.
For in Christ all the fullness of the Deity lives in bodily form, and in Christ you have been brought to fullness.
The Reformers summarized salvation with five 'solas': grace alone, faith alone, Christ alone, Scripture alone, to God's glory alone.
Epistle to the Colossians