Today — January 11, 2016 — John Piper turns 70. I ‘met’ John Piper in 2000 when I was 19 years old and my summer mission trip leader had us read The Pleasures of God together. I was transfixed, and transformed.

Never had I encountered such an explicitly God-centered worldview or such compellingly clear theological prose. My way of seeing the world was revolutionized. Everything else moved to the edges, and God moved to the center.

A year later, in March of my junior year, I attended an evening session of the Shepherds’ Conference at Grace Community Church and heard Pastor Piper preach for the first time. Another worldview explosion went off in my mind and heart as I recognized the radical nature of the Christian life and calling. I can still remember exactly where I was later that night as I recounted to friends what was happening in my heart.

In the years that followed, I read many more books, listened to many more sermons, attended many more conferences, and followed Pastor Piper’s ministry from afar, learning so many important things in so many different ways, having my worldview shaped by someone I came to consider a mentor.

Now, more than 15 years later, I am a 34-year-old husband and father of 4 working at a Bible college. I know so much better than my 19-year-old self just how incredibly hard it is to be faithful, to be consistent, and to keep the glory of God and the kingdom of Christ first in my heart. As I’ve walked the rugged path of Christian discipleship, my appreciation for those who’ve stayed faithful has deepened exponentially.

Still, although my perspective continues to ripen, I’ll always look back with fond memories on those earliest years of my Christian walk as I learned that radical Christianity was normal Christianity and that God and his purposes were so much bigger than I had ever imagined. And I will always remember that by the grace of God and under his sovereign will, much of that learning happened as I listened to the Holy Spirit declare the Word of God through the preaching and writing of John Piper.

Now, if you see a polarized relationship between thanking people and thanking God, or if you tend to look sideways at all famous Christians, or if you think that all extended gratitude for a human being is hagiography no matter their contributions to the kingdom, it might be best to skip the points below. But if you can join me in thanking one of God’s servants for decades of faithfulness that have shaped a generation of Christians, keep reading.

Because like so many others of my generation, when I really stop and reflect on my life as a Christian these past 18 years, I am overcome with gratitude for John Piper’s incalculable influence. Here are 70 reasons why.

Thank You, John Piper