"To whom also (the Lord) shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God:"
Passion from the Latin patior, passus, means "to suffer." It refers to the torturous events of the atoning sacrifice of the Lord Jesus Christ. The "infallible proofs" spoken of in this verse are the Savior's many appearances as a resurrected being. The Greek word here means, literally, "sure signs or tokens," according to D. Kelly Ogden and Andrew Skinner in "New Testament Apostles Testify of Christ."
And although Jesus refused many requests for miracles — and indeed condemned some — signs nevertheless naturally assisted the faith of skeptics throughout his ministry, including his apostles. The Lord's resurrected appearance among his apostles was indeed a sign in itself, but it appears more proof was needed for the "troubled" 10 apostles. Only after he showed them his sacrificial tokens and ate meat before them did they fully believe.
"These unquestionable evidences of the Visitant's corporeity calmed and made rational the minds of the disciples," James E. Talmage explained in "Jesus the Christ."
The fourth gospel regularly describes miracles as signs of Christ's godhood, and frequently attributes them with evidential value. To question a miracle's value on one's belief is to dangerously question those like Doubting Thomas, whose incredulous attitude toward the Savior's resurrection must only be judged with "caution and charity," Elder Talmage wrote. The Lord still accepted Thomas' eventual belief and adoration, but clearly illustrates two kinds of faith: one, faith that is dependent on signs, which, if not altogether condemned, is by Jesus depreciated; and two, a greater faith: "blessed are they that have not seen, and yet have believed."
The "forty days" refers to Christ's five or six-week post-resurrection ministry, where, on one occasion, more than 500 people witnessed the resurrected Savior.
Jake Hancock