That word tribulation is the word thlipsis in the Greek. It means pressure (literally or figuratively): -afflicted, (-tion), anguish, burdened, persecution, tribulation, trouble. We all go through pressure in life. When we do we gain our strength and encouragement from one another to not give up our faith but to continue understanding that this to will pass. Everything we experience in this life is only temporary. The paradisiacal life we have in Christ Jesus is eternal. So, hold on to what you have (your faith in Christ) and do not give up or yield.