For example, Psalm 25:8-9 (ESV) says "Good and upright is the Lord; therefore he instructs sinners in the way. He leads the humble in what is right, and teaches the humble his way."
Would it be wrong of me to change it to this?
The Lord is good and upright, and he teaches sinners to be the same way. He leads them to do right and teaches them to be as humble as he is"
The question here would be is your paraphrasing accurately convey what the text is actually saying; because no there's nothing wrong with paraphrasing something in order to help others understand easier, it is problematic if we are missing the point of the text ourselves and then pass on our own misunderstanding to others.
In this instance, I don't think your paraphrase is quite accurate in capturing the intended meaning of the text. The point instead here is that God is good and just and thus He instructs those who are wayward to walk the straight path of justice and goodness; it is the humble who can hear God's instruction and receive it; as the arrogant will stubbornly refuse God's correction.
If I wanted, for example, to point to God's humility and the calling upon us to be humble in imitation of God's humility, I would instead point to Philippians chapter 2, where St. Paul speaks of Christ's humility as the example we are to have. As Christ, though Himself truly and very God, willingly and with humility becomes man, becoming a slave, and is obedient even to the point of death on the cross. It is in the Incarnation that we encounter the humility and lowliness of God in His kindness and love toward us, in His throwing Himself away in love that we might be reconciled to Him, and here we see the example of the sorts of people we ought to be as servants and disciples of Jesus Christ. The One who made heaven and earth, and before Whom every knee will bow and tongue confess is the One who emptied Himself, humbled Himself, and bore the shame and suffering of the cross for us. If God the Son Himself did not exploit His glory for personal gain, but willingly became a slave, how much more should we follow this example and humble ourselves, lower ourselves, serve others with meekness and love?
But in Psalm 25:8-9, the point is instead that the humble will hear and receive the word of God; though I might also recognize that seeing as the Law condemns, then what we find here is the sad and tragic truth that we are not humble, but rather we are arrogant, for we do not obey God, we do not follow the straight path--and so we find that we have not humbled ourselves in meekness and so, as St. Paul says in Romans 7, the Law which is holy and is supposed to give life actually compounds our sin and breaths death to us. So wretched man that I am, who will save me? Thanks be to God for Jesus Christ, and so therefore there is now no condemnation for those who are in Christ Jesus.
-CryptoLutheran