How do we know that life is uncertain according to the Bible?

Scripture emphasizes the uncertainty of life in several passages, encouraging believers to recognize their fragile condition. For instance, 1 Chronicles 29:15 notes, 'For we are strangers before thee, and sojourners, as were all our fathers; our days on the earth are as a shadow.' This metaphor points to the unpredictability of human life. Life can change in an instant, reminding Christians that ultimately, their security rests not in earthly possessions or health, but in Christ alone. As such, believers are called to lean on God's providence and to prioritize spiritual rather than temporary pursuits.