One of the many "beatitudes" spoken by our Lord was, "Blessed are those who have not seen, yet have believed". Jesus said this after his crucifixion and resurrection, when he came into the midst of his disciples and showed himself alive from the dead.
Thomas had been absent on a former occasion when the others had seen Jesus. He had been unwilling to believe until he had personally seen Jesus. On this next occasion, Jesus showed himself to "doubting Thomas", and said to him, "Be not faithless but believing."
Now Thomas, having seen with his own eyes, and touched with his own hands, willingly confessed his faith. He exclaimed, "My Lord and my God!."
Jesus replied, "Thomas, you have believed because you have seen me." Then Jesus added that beatitude: "Blessed are those who have not seen, yet have believed". (John 20:29).
Those, like Thomas who believed having seen Jesus, are certainly blessed. But those who have not seen, yet have believed, are equally if not more blessed. We can see this from three aspects...
John links this story to his purpose in writing his book "that you might believe and have eternal life" (John 20:30-31). He writes for the likes of you and me who have never seen Jesus. More than 500 people saw the risen Lord (1Corinthians 15:3-8).
By contrast, millions have never seen him, yet have believed. Yet every one of us is blessed and known by name (Revelation 3:5). Our faith rests on the sure word of prophecy and testimony of the scriptures (2Peter 1:16-21). John says the same in the prologue of his 1st epistle (1John 1:1-4).
The saying goes, "Seeing is believing". For us the saying is reversed: "Believing is seeing". We have believed without seeing; and we shall see because we believe.
"Every eye shall see him" (Revelation 1:7). "We shall see him as he is" (1John 3:2-3). Of course, even unbelievers will see Jesus, but not in the same way as believers that is to say, "admired by all who have believed" (2Thessalonians 1:9-10).
"And though you have not seen him, yet you love him, and though you do not see him now, you rejoice with joy inexpressible and full of glory" (1Peter 1:3-9). Our faith can grow into boundless love and devotion, and into a joy full of glory.
I suppose we have all wished that we had lived back in Jesus's time. If time machines were possible, we would probably want to travel back to that time. However, we live nearly 2000 years later, and have never seen Jesus.
Nevertheless we have learned that our faith in Jesus Christ is well founded, and through that faith we will one day see him. Meanwhile our faith lacks nothing for not having seen him yet, and in our faith we can have great joy.