Gambling
What is it? Take a risky action in the hope of a desired result.
When Hebrews says that "faith is the assurance of things hoped for" it is acknowledging that we are taking a risk.
In these verses Paul makes it clear he is risking everything:
12 Now if Christ is preached that he hath been raised from the dead, how say some among you that there is no resurrection of the dead? 13 But if there is no resurrection of the dead, neither hath Christ been raised: 14 and if Christ hath not been raised, then is our preaching vain, your faith also is vain. 15 Yea, and we are found false witnesses of God; because we witnessed of God that he raised up Christ: whom he raised not up, if so be that the dead are not raised. 16 For if the dead are not raised, neither hath Christ been raised: 17 and if Christ hath not been raised, your faith is vain; ye are yet in your sins. 18 Then they also that are fallen asleep in Christ have perished. 19 If we have only hoped in Christ in this life, we are of all men most pitiable.
We call it faith, but remember, hope that is seen is not hope. Faith is the substance of things not seen.
Ephaphroditus risked his life. All of the martyrs risked their lives. By comparison risking a few dollars in a game of chance is a shabby counterfeit, they do it for the hope of gain and because they love money they will become addicted.
They have a shabby hope, a shabby love, and no clue what real faith is, so they call it chance.
By comparison giving your life to Jesus because you love Him and you have a hope for a better city and you believe in God's word enough to hazard your life. That is the reality of gambling.