The Greek adverb hagnōs means 'purely,' 'with sincere motives,' or 'in a holy manner.' It derives from hagnos (G53, 'pure, chaste, holy') and describes the manner of an action — with genuine, uncontaminated intent rather than ulterior motives.
Paul's use of hagnōs in Philippians 1:17 illuminates a persistent temptation in ministry: using the gospel for personal advancement rather than Christ's honor. Those who preach Christ from selfish ambition do not proclaim it 'purely.'
The call to purity of motive runs throughout the New Testament. 'Blessed are the pure in heart' (Matthew 5:8). Christian ministry is to be done hagnōs — without self-serving agenda, motivated by love for Christ and others.