I don’t stress with the chapter and verse reference at first. Young children seem to easily memorize the words, but can struggle with the book and numbers, IMO. Actually, so do I—I can remember lots of words to verses but I still struggle to remember the chapter and verse numbers, although I usually can remember the book it’s in. Like Sonya said, if you remember the verse itself, you can find it if you want.
However, that being said, there are some verses that we memorize that I think the children ought to know the chapter and verse as well. John 3:16, for example. I move on with a new verse when we completely memorize an old one, but I have a simple game that we play to work on the chapter and verse of some important scriptures. When I have several, like 6 or so, that I’d like the children to remember the reference, then I take a small piece of posterboard and divide it into 12 rectangles about the size of an index card in two columns. I write the references down one side of the posterboard, make additional copies of the verse cards I want us to do this with, without the reference printed on them, and leave them out and periodically ask the children to place the verses next to the reference. This really seems to help retention of this. I play this game myself to help ME, also. 🙂
Another thing I’ve done is to try to find a keyword to attach to the reference. I have a sequence of verses I’d like my children to be able to recite WITH the reference. So we simply memorize the verses themselves. Then we memorize a keyword to go with each verse. For John 3:16, for example, you might choose LOVED and a picture of a heart. Then, after the verse and the keyword are associated, associate the keyword with the reference. You can do this with the game I mentioned above–except they match the keyword to the reference.
I don’t know why, exactly, but my kids can do quite a string when we do things like this. We also do keywords for each sentence in a very long passage, which really seems to help when a child gets partway through and then gets stuck; he can tick off “Ok, I got X and Y and next is Z, so the next sentence is . . . “
HTH! Remember the virtue lies in the Word of God, not in the references–those are merely for our convenience. I console myself with this all the time when my brain refuses to come up with the reference of a verse I want. 🙂
Michelle D