Watching has to do with being ready for His appearing. But what does it mean to be ready? Perhaps the simplest statement made by the Apostle John related to this is:
1Jn_2:28 And now, little children, abide in him; that, when he shall appear, we may have confidence, and not be ashamed before him at his coming.
Jesus and the Apostles showed us that even for believers it is possible to be found in two very different conditions as the Lord comes. He can find us sleeping, and come upon us as a thief. We could “ashamed” before Him at His coming. But John tells us here that if we abide in Him, we can have confidence at His coming. While there are many warnings about the consequences of not being ready, there are also many promises about being joyful:
2Ti_4:8 Henceforth there is laid up for me a crown of righteousness, which the Lord, the righteous judge, shall give me at that day: and not to me only, but unto all them also that love his appearing.
Jud 1:24 Now unto him that is able to keep you from falling, and to present you faultless before the presence of his glory with exceeding joy,
Heb 9:28 So Christ was once offered to bear the sins of many; and unto them that look for him shall he appear the second time without sin unto salvation
1Th 4:16 For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord. Wherefore comfort one another with these words.
I have found that any time I begin to look again at the prophetic scriptures related to His coming, especially in the New Testament, it has a very sobering effect. I have found again and again that I am “intoxicated” with this world. I fear for myself and those close to me that we might not be found ready. It usually is accompanied with much soul searching and regret over missed opportunities, and long periods of failure and living entirely for myself. But I keep coming back to His promises. He who began a good work in me will complete it until the day of Christ. He is able to keep me from falling and to present me faultless before the presence of His glory with exceeding joy. There is a crown of righteousness for those who love His appearing. And when He comes it will be without sin unto salvation. The soul searching and introspection is fine as long as it brings me to repentance and faith.