I feel grateful to God for the immense support we received from Mr. Kim OkJa, a dedicated missionary from Korea. With his unwavering support, our cell group was able to construct a beautiful church building that we can all be proud of. The construction of the building was a huge undertaking, but Mr. Kim OkJa was always there to encourage and motivate us. 

Finally, on March 18, 2023, we were able to hold an inauguration program to open the doors of our new church building. It was a momentous occasion for all of us, and we felt incredibly blessed to have Mr. Kim OkJa there to share in our joy and celebrate with us. The building was constructed with the highest quality materials and is a testament to the hard work and dedication of everyone involved. 

We owe a debt of gratitude to Mr. Kim OkJa for his unwavering support and his tireless efforts to make our dream church a reality. Without him, we would not have been able to achieve this amazing feat.

That's wonderful news! Here's a refined version of your statement:

"We are immensely grateful to Mr. Kim OkJa, a dedicated missionary from Korea, whose generous support enabled the construction of a church for our cell group. Following the completion of the building, we joyfully gathered for its inauguration ceremony on March 18, 2023, marking the official opening of the new facility for worship and community gatherings. Mr. Kim's partnership and commitment to our mission have been instrumental in advancing our spiritual journey and outreach efforts. We give thanks for his unwavering support and God's abundant blessings upon our congregation."