Psalms 119:9
9How can a young man keep his way pure? By living according to your word.
Wesley: A young man—or, any man; he names the young because they lack wisdom and face great temptations. Cleanse—purge from all filthiness of flesh and spirit.
Wesleyan Arminians see a practical, sincere answer: purity comes by taking heed according to God’s word. The word is public lamp; youth (and every hearer) may guard the way by it under grace.
Calvin: nothing is pure in life until men make a complete surrender to the Lord’s word. Youth is named because the young stand where two ways meet; no advice avails unless the law of God is adopted as rule and guide. Early regulation of manners is urged; delay hardens vice. If the law can restrain youth’s impetuosity, how much more maturity.
Purity is by the word as rule, not by self-pique on works. Surrender to Scripture is the only sure protection.