Here is a trustworthy saying: If we died with him, we will also live with him; if we endure, we will also reign with him. If we disown him, he will also disown us; if we are faithless, he will remain faithful, for he cannot disown himself (2 Timothy 2:11-13).
In God’s sight, there is always a direct link between the difficulties we may have as believers here and the joy and glory that wait beyond.
If we endure, we will also reign with him. It is wrong to understand those verses as though they mean that by your suffering and your enduring hardship you win the right to a crown. That is never the case in the Scriptures. We do not win a reward; we do not merit anything from God ever; no faithful service puts God in our debt and obliges Him to give us a reward.
What these verses are saying is that this is a test of the reality of our faith. If we really are Christ’s, if He has genuinely come to dwell within us, that fact will always manifest itself by our willingness to suffer with Him; to give up some things for Christ’s sake; to resolutely set ourselves against the allurements and temptations of this age and live a different lifestyle. That is the manifestation of true Christian life. If we have these genuine desires to live for Christ, of course it is absolutely certain that we shall share with Him because we belong to Him.