Note:
I wanted to share this insight by a new contributor because I appreciate the spirit of his encouragement: we must remind each other about the coming of the Lord Jesus, but we must not be divisive or condemning about those who do not understand this coming exactly as we do. The important point: we must be ready in the ways the New Testament writers instruct us to ready ourselves. Today is the Lord's day. In the earliest days of the church, the following words were probably used as a benediction as believers left their gathering and went back into the world to live for Jesus. I believe David's words that follow will help us do just that:

Come, Lord! (Marana tha!) The grace of the Lord Jesus be with you (1 Corinthians 16:22-23).

How can we prepare for the Second Coming of Christ?

At first glance, preparing for the Lord's coming appears difficult, if not impossible, because nobody knows the day or hour He will come (Matthew 24.32, 36-39; Matthew 25.13; Mark 13.32) and daily life will continue as usual until the last moment (Matthew 24.38-39). However, early Christianity provided a very practical answer:

We are to continue to live good Christian lives as preparation every day, whether we believe the Lord will return this afternoon or in the distant future.

In discussing the Second Coming, the great apostle exhorted Christians with these words:

You ought to live holy and godly lives as you look forward to the day of God and speed its coming (2 Peter 3:11-12 NIV).

And so, dear friends, while you are waiting for these things to happen, make every effort to be found living peaceful lives that are pure and blameless in his sight (2 Peter 3:14 NLT).

We must not scoff at the prospect or likelihood of Jesus' return (2 Peter 3:3). In all our preparation, we are to remain calm and level-headed, not becoming upset or alarmed (Matthew 24:6; Mark 13:7; Luke 21:9; 2 Thessalonians 2:2).

A first-century Christian source outside the received Scriptures is the Didache — which may have been written before some of our existing New Testament documents — exhorts Christians to watch and be ready at all times.

Origen, a Bible scholar in the first half of the third century, found a symbolic and moral significance to the bells on the High Priest's robe, which could always be heard while he served (Exodus 28.31-35). Origen saw this as a reminder that we are never to be silent about the End Times. We should always discuss and speak about them as we live in the last days. By remembering the coming of the Lord in this manner, we will never sin.

Origen also composed the first text of Christian systematic theology, titled On First Principles. In the chapter on the end of the world, he cautioned readers to treat the subject with care and caution, as a matter of discussion and further exploration among Christians, rather than as cut-and-dried dogmatism. Allowing no scope for intolerance or dogmatism, Origen would disapprove of religious groups in his — and most certainly in our day — that arrogantly claim they alone possess the only correct interpretation of Bible prophecies and teachings about the End Times to damn and exclude Christians that do not agree with them completely. There should be room for dialog when talking about the Second Coming, this respected Christian teacher warned.

Our best preparation for the Last Days is living upright, and pure Christian lives.

Our best preparation for the Last Days is living upright, and pure Christian lives. We should spend the time allotted us in brotherly love and co-operation in good works. We should practice toleration in nonessentials while eagerly sharing the good news of Jesus with unbelievers. Also, we should warn one another when we encounter a false prophet or deceiver who would mislead us and them about the End Times, especially anyone who would discount the importance of Jesus' return.

In short, we should follow Paul's advice at the conclusion of one of his passages on the Second Coming:

So then, brothers and sisters, stand firm and hold fast to the teaching we passed on to you, whether by word of mouth or by letter (2 Thessalonians 2.15).

Paul sums it up well as he instructed his student minister, Titus, in what to do and teach in his own ministry:

For the grace of God has appeared that offers salvation to all people. It teaches us to say "No" to ungodliness and worldly passions, and to live self-controlled, upright and godly lives in this present age, while we wait for the blessed hope — the appearing of the glory of our great God and Savior, Jesus Christ, who gave himself for us to redeem us from all wickedness and to purify for himself a people that are his very own, eager to do what is good (Titus 2:11-14).