(NIV) Stand firm, and you will win life.
(NASB) By your endurance you will gain your lives.
(YLT98) in your patience possess ye your souls.
The context here is suffering persecution for your faith in Christ. But it seems to me that this statement is generalizeable to the whole Christian life.
Of course, this statement is not undermining the sufficiency of grace, but rather, highlighting the mysterious duality of human collaboration with God.
Heavenly Father, please give me strength to persevere. Thank you for walking with me. Please give me wisdom to know what I should be doing, and please give me boldness to obey. I love you, and I pray in the name of Jesus.