When Christ saw Mary after the resurrection, why did He say, “Touch me not”? What was different about His body that would have made it wrong to touch Him?

There is no question that His body after the resurrection was a flesh-and-blood body. There was nothing “wrong” with His body that would affect us if it were touched. As a matter of fact, when Thomas doubted the resurrection, Jesus told him to put his hand into the wound in His side. So He was not talking in the former passage of actually touching.
The command to Mary had more to do with holding on or grasping Him in order to keep Him here on earth. This time after the resurrection was not just a get-together requiring the usual gestures of welcome or hugging. Something had taken place since His followers had last seen Him. His work on the cross had been accomplished, and this was a time for a new relationship. He appeared here to show Mary this resurrected body before He went to be with His Father. This was not a time for holding on to the former relationship of human contact. Mary seems to have understood it perfectly and was not offended by His admonition. She went to tell others of His resurrected appearance.

What does it actually mean in Revelation 2 when the angel of the church says, "Thou hast left thy first love"?

"Losing your first love" is quite an indictment in any intimate relationship, but in the divine relationship between an authentic Christian and his Lord it is even more devastating. In this case the first love is Christ. Losing love for Him can happen in this old world when we are distracted by any other influences or human relationships to the point where Christ is often overlooked.
Each member in this congregation had enjoyed the gift of the Holy Spirit as a result of the ministry of Paul (Acts 19). They had gone from a warm and loving relationship with the Savior to the coldness resulting from other things. Their passion for Him had lost its intensity.
This can happen to any of us. We are distracted by worldly things, by service that has just become rote, or an obsession to get the job done without considering that we’re doing it for Jesus.
What is meant by the phrase "the poor in spirit" in the Beatitudes?

The Beatitudes speak of the "Happy Ones," those who are blessed because they don’t think of themselves more highly than they should.
I’m often concerned about those who get caught up in their own gifts and importance and become almost arrogant before others. Whether a factory worker or a preacher, we can become so caught up in ourselves that we rarely appreciate the gifts of others or give them the acknowledgement and honor they deserve. We can be so impressed with how far we’ve come in our earthly or divine gifts or abilities that we forget that any gift or ability comes from Christ, and without Him or His power we would be nothing.
The humble lean on God. The humble man or woman is well aware that their accomplishments are for the glory of God. The humble live with the indwelling principle of Paul: "I have been crucified with Christ and I no longer live, but Christ lives in me" (Gal. 2:20).
By Mike Kellogg, Moody Radio Host
Mike Kellogg has been with the Institute in Moody Radio for more than 40 years, beginning in 1972. For many years he was the reader on Continued Story and began hosting Music Thru the Night in 1982. He also reads the Today in the Word devotional on air for Moody Radio. He is a graduate of Cedarville University, and has served as adjunct faculty in English and Speech Communications at Moody Bible Institute. He is married to Nancy, and they have 6 children and 16 grandchildren.