John, in mentioning the second coming of Jesus, could have referred to it as a comfort for believers, as is done elsewhere in the New Testament. But he is led to mention it in the way that it will affect unbelievers. The Day of Judgement will be an occasion when the glory and authority of Jesus will be obvious. On that occasion, gathered before him will be those who have opposed him, including those who brought him to the cross, described here as those who pierced him.
What does John stress about the return of Jesus and how it will affect unbelievers? John’s use of clouds is a way of referring to the glory that Jesus will have when he returns. Moreover, the return will have a universal effect because every eye will see him, but the sight will not bring about rejoicing but regret, because the observers will realise that he is coming as Judge. We may be surprised at John’s response, ‘Even so. Amen.’ The reason for his reaction is connected to his desire for Jesus to be honoured and for sin to be dealt with.
Spurgeon, in a sermon on this verse, points out that the second coming should be vividly realised, zealously proclaimed, unquestionably asserted, and demanding immediate interest because he is on the way.
It is not clear who is speaking in verse 8. Some commentators say that it is the Father and others say that it is Jesus reminding the readers of his deity. If the Father is speaking, he says three things about himself: he is the one who started everything and who will wind it all up (the Alpha and Omega); he is the one who had no beginning and has no end; and he possesses all power. If the Son is speaking, he says the same three things about who he is. Whichever one is speaking, the words are very encouraging for believers.
When Jesus returns, everyone will know that he is the eternal God, with almighty power.