Not only for its beauty and "steadfast reference" to its biblical context of being firm, unwavering and resolute in purpose, but for me it's the verse included that speaks to my heart. 
1 Corinthians 15:58 (NASB95)--Therefore, my beloved brethren be steadfast, immovable, always abounding in the work of the Lord, knowing that your work is not in vain in the Lord.
The verse is so memorable to me because it was given to me in in 1997 in a gymnasium in Budapest, Hungary. Cots were spread out for us to sleep on until there until we could leave to travel to Kővágóörs, a village of 900 inhabitants. We would be at Cornerstone House, near Lake Balafon to teach English as a second language.
Wide open showers were provided in the gym but not a single shower curtain. Not to worry..... as a "just in case" gal I had packed a shower curtain. Plus, friend Pam had sent a large jar of peanut butter with me & I became everyone's friend because I had American peanut butter
A gentlemen helping us unload asked if this was a first time mission trip on a foreign field for anyone. I raised my hand. That's when he gave me the note with the verse to encourage me to "keep on keeping on" in the work of the Lord!
That verse continues to speak to my heart.
