New Defender's Study Bible Notes
4:15 we. It is very significant to note that, in these relatively early years of his ministry, Paul considered it very likely that he himself would be living when Christ returned: “We which are alive and remain unto the coming of the Lord,” he said. This divinely inspired conviction proves that the rapture has always been imminent, not contingent on other events that must come first. That is why Jesus urged His disciples always to be watchful and ready for His return (e.g., Matthew 24:42,44).
4:15 prevent. “Prevent” is an earlier English way of saying “anticipate” or “precede” (from the Latin for “come before”).