So with Matthew 26, we're really getting close to the end of all of this, and Jesus is getting close to the end of his life. (The question as to whether he forewarned his disciples of his death I covered in Matthew 20.)
There's a story in verses 6-13 in which a woman pours some expensive ointment on Jesus' head, and there is a question of whether it was a wasteful thing to do. While I think the case can certainly be made that it was truly wasteful and could have been better spent on helping the poor, but there are a few things to note. The parallel telling of the story from the Gospel of John points out that it was Judas Iscariot in particular who was complaining, and the reason he was complaining was not that he cared about the poor, but because he wanted the money for himself. (The passage also says that the woman, who is there identified as Mary of Bethany, poured it on Jesus' feet, a contradiction the SAB missed, but I'm sure it'll be added soon after this post is published.) Also note that Jesus is making a point in two parts. First, that he's being anointed for burial, which shows that the woman has a deeper understanding of what's going on, and second, that since he's about to die, this is the last time the disciples will have a chance to do anything for/with Jesus before he's dead, while caring for the poor--while yes, it's important--is work that will never end.
Anyway, it's Passover, so Jesus and his disciples get together to have a traditional Passover supper (commonly known as a "Seder") which comes to be known as the "Last Supper". Jesus takes the occasion to reinterpret a lot of symbolic items from the Seder in respect to his death and resurrection. A lot of these are open to interpretation, and the SAB marks the passage with the "interpretation" icon, but I'm not just going to address the items the SAB brings up, but bring up a few others.
In verse 26, it says that Jesus takes bread, blesses it and breaks it, saying "Take, eat; this is my body." (This bread is very specific bread, as it happens. At a Seder, only unleavened bread is eaten (leaven being symbolic of evil) and there is a special thing done with some of the bread which I believe is symbolic of the Trinity and the death of Jesus. Three pieces of bread are set aside in a special pouch, and the middle one of the three (the afikomen) is broken, taken away and hidden, and then brought back to the table. This piece is put back together, and then everyone is required to eat a piece of it.) Then Jesus takes a cup of wine and tells them "Drink ye all of it, for this is my blood..." (This cup of wine is the third of four cups of wine that are had during the Seder, this one being known as the "Cup of Blessing".) So Jesus is taking traditional elements of the Seder and reinterpreting them in a messianic manner, which leads to the issue of various interpretations.
As the SAB points out, there is doctrinal difference among Christians over whether this is literally the body and blood of Jesus. Most Protestants consider it to be symbolic, while Catholics believe in the doctrine of Transubstantiation, that is, that the bread and wine will somehow become the actual body and blood when consumed. What the SAB apparently doesn't know (or I assume they'd mention it) is that the Jehovah's Witnesses believe that communion is meant only to be taken on Passover (while most Christian churches will do it weekly or monthly). Admittedly, there could have been more clarity given, and it's a bit sad that despite the lack of clarity, pretty much every church is 100% convinced that their method and doctrine is correct, and others are mistaken, sometimes to the point of heresy.
The SAB asks "Is it okay to drink alcohol?" and I'll stand on my answer given in the middle of this post, which boiled down largely to a common sense stance of "It's okay in moderation."