The disciples were probably disappointed in His answer. It is somewhat of a disappointment even to us that God is purposely withholding the time of the Kingdom's establishment, of the second coming of Jesus Christ. He has a good reason for doing so. In His wisdom, He can see He can produce far more that is better and good in us if we do not know when Christ will return.
For starters, we would relax in a way that is not good if we knew when Christ is going to return. Not knowing gives us a much greater opportunity to use faith in trusting God.
Jesus' answer to them can seem somewhat enigmatic. However, even though He tells them, "It is not for you to know the times or the seasons," which discouraged them, He continued with something that is very encouraging. He tells them that they would receive the Holy Spirit and power that would enable them to endure what faced them and complete their divine mission, which was of the highest priority at that time.
This principle still applies to us. We do not know when Christ will come. We do not know when God will establish His Kingdom, nor how much trouble we may have to experience before then. But He is saying to us just what He said to them: "You will be given power that will enable you to endure, overcome, and grow during the time I want you to serve Me." He has not left us alone. He has not left us without the resources to do what we have to do.
It is nice to know what was on the disciples' minds on this significant occasion. It is good to keep the same, important thought at the forefront of our minds too. In the model prayer—called the "Lord's Prayer"—Jesus says near the beginning, "Your kingdom come" (Matthew 6:10). It is a top priority that we ask God for that to occur.
The return of Jesus Christ and the establishment of the Kingdom of God was probably a far more compelling drive in their minds than ours because of their visible and audible firsthand, face-to-face relationship with Christ. The Kingdom of God held a major role in the Good News that He preached every day in their presence.
It was likely a while before they realized and came to grips with the fact that they had to revise their top priority. Christ told them that their new top priority was to preach the gospel. The preaching of the gospel must come first, then the Kingdom.
Did their hope wane because their foremost goal was delayed? Did the establishment of God's Kingdom seem ever more distant as time went on? Did they lose faith because they perceived it would not come in their lifetimes? We need to ask ourselves such questions.
