Why do certain Christians claim that getting a person into scriptures is all you need to do; the  Holy Spirit then will change them?

My response : Definitely Not True (I will address the why part at the very end)

That is downright unscriptural. The Bible Does Not Acquit The Mature Believer From All Responsibility To The Spiritual Well-being Of Others.

The Lord Almighty who created us and gave human beings “freewill”, wants each of us to love Him voluntarily. God essentially wants an intimate and close relationship with each one of us as is clear

"That which we have seen and heard declare we unto you, that ye also may have fellowship with us: and truly our fellowship is with the Father, and with his Son Jesus Christ." [1 John 1:3; KJV]

However, it is impossible for fallen man to have any relationship with a Holy God. It is essentially this question that God poses in the Book of Amos (ref Amos 3:3).

… And it is this that God seeks to rectify.

• The initiative for Everything is in the hands of the Lord. Faith in the Lord is essential but God has seen to it that the one who is a sincere beleiver, can get it even if they don't have it (ref Romans 10:17). God - who is Love (ref 1 John 4:8) - wants us to love Him with all our hearts and let our obedience stem from a heartfelt desire to be pleasing in His sight.

1. He draws us to Himself through His word, through His Holy Spirit who is responsible for our regeneration
2. While this seems to convey an air of passivity, nothing could be further from the truth. The Bible does say that the evil one flees IF we stand strong in the faith (ref James 4:7). However, this is a very big IF and this is exactly where the mature believers in the Lord should step up to help the others.

.There is nothing passive about mentorship (ref Colossians 3:16) and/or Intercession (ref Colossians 4:12). Read my post on Intercession here 👇

Abraham World View · October 5

The concept refers to the act of mediating on behalf of another, particularly through prayer. Divine intervention and blessings are sought for others. Not only is the practice of intercession deeply rooted in the Bible but it is a significant concept in Christian theology, especially as it embodies the Biblical values of selfless love, compassion, and faith. “And he saw that there was no man, and wondered that there was no intercessor: therefore his arm brought salvation unto him; and his righteousness it sustained him.” [Isaiah 59:16; KJV] i) The heart of the intercessor aligns with that of the Lord. A distinct lack of individuals willing to plead on behalf of others and to advocate for justice, mercy and righteousness prompts God to work swiftly to enact salvation. However it would be a fallacy to equate Intercession with arm twisting God, for He is sovereign (ref Jeremiah 7:16). ii) A concept deeply rooted in scripture and exemplified by numerous biblical figures and teachings is, “Selflessness In Service”, which is a central theme in the Christian faith. Ruth's decision to leave her homeland and care for her mother-in-law (ref Ruth 1:16-17), reflects a profound selflessness, prioritizing Naomi's well-being over her own future security and is a poignant example of selflessness. Its not just an abstract ideal but a practical calling for Christians involving daily acts of kindness, generosity, and humility. Intercession puts the needs of others over self and is one such. iii) All genuine believers are called to be a “royal priesthood” (ref 1 Peter 2:9), meditating between a holy God and a broken world through prayer. Intercession is an expression of the priesthood of all believers. iv) One of the central attributes of God is compassion 👇 Genuine believers are required to emulate that divine quality. It is very closely aligned to intercession as both involve a deep awareness of the suffering of others, coupled with a desire to alleviate that suffering. Intercession is an outpouring of this divine attribute expressed through prayer (ref Galatians 6:2) v) Humility is not merely an attitude but a pathway to receiving God's blessings. Both humility and intercession are intrinsically linked. Humility is the soil in which all other Christian values take root. It is essential in intercession, as it allows individuals to acknowledge their own limitations and the need for God's mercy. Additionally, it fosters a spirit of dependence on the omnipotent God, alignment with His heart and values. This opens the door for effective intercession. Aaron's intercession for Miriam (ref Numbers 12:11-12) — a) Underscores the importance of humility and repentance in the face of sin. b) Depicts the power of intercessory prayer and the mercy of God who despite His anger provides a path to restoration (ref Numbers 12:14). The ardent believers align with God's purposes through humility and through intercession, he/she participates in His redemptive work in the world. The OT prophet Samuel understood that a reluctance to intercede for others was a sin, when he said - “Moreover as for me, God forbid that I should sin against the Lord in ceasing to pray for you: …” (ref 1 Samuel 12:23). Later on it was reiterated in the New Testament too 👇 The entire ministry of Our Lord is an act of intercession, culminating in His vicarious and sacrificial death on the cross. Moreover, His intercession is ongoing, as He sits at the right hand of the Father, advocating for believers (ref Hebrews 7:25). His high priestly prayer (ref John 17), is a profound example of His intercessory work, seeing that He prays for His disciples and all future believers, asking for their protection, unity and sanctification. In short, intercession is - i. Obedience to the Almighty And ii. A means by which God's grace and mercy are extended to others. I present an example below 👇 The personal discipline of the individual is complete only when the believer has successfully passed from the sphere of personal sorrows to interceding for others. Job manifested his obedience to God and his true love for his friends when he readily forgave them and moreover prayed for them. This very act of self-oblivion and self-sacrifice brought about - i. The deliverance of Job from the distresses and miseries afflicted by the temporal state of bondage to the evil one. ii. Job was restored from his series of protracted trials to increased prosperity as his estate increased. iii. Job's mediation and intercession on behalf of his friends, led to their restoration and acceptance by God.

https://abrahamworldview.quora.com/The-concept-refers-to-the-act-of-mediating-on-behalf-of-another-particularly-through-prayer-Divine-intervention-and-bl?ch=10&oid=256831189&share=6524532e&srid=okRx&target_type=post

Intercessory prayer is placed at the forefront of Christian duty and not as an afterthought (ref 1 Timothy 2:1). Praying for others is central to spiritual leadership and selfless love.

• The Great Commission calls for dynamic training and rectification of errors. It is about making disciples and discipleship is not merely about transferring information or doctrine; it is about shaping lives to reflect the character of Jesus as is stated explicitly in Philippians 2:5.

Infact, this is quite clearly stated in scripture 👇

God has always called His ardent followers to be the Watchman On The Wall. We are the Bride of Christ, His Body but we are also called to be the “salt” on this earth … and salt preserves from rot and corruption.

Failing to warn our neighbour if he/she strays away from the truth of the gospel, can be construed as Not fulfilling the responsibility of a “spiritual watcher”, and thus by extension Not obeying the Lord.

Now we come to the “Why” part of the question :

From the above it should be clear that there are many factors at work here.a combination of

1. wrong doctrines
2. pastors who value the number of church attendees, over the undiluted word of God
3. The predisposition of the lukewarm christian

They all contribute to this wrong notion.