Why should you teach two verses of the song completely separate from each other with different activities to teach the song?
The brain is a sorter. Every night as you sleep, the brain takes the different experiences of the day and sorts through them, lodging them for storage and analyzing different aspects of the experiences. (For some interesting and very accessible research, see John Medina, "Brain Rules")
When we teach two of the verses to a song together, the brain will often lodge the words of both verses together. When we try to sing the song, it can sometimes be tricky for the brain to recall the right words for the exact verse. For instance, when singing a hymn from memory at home without a hymnbook, you might stumble with which phrase is in the second verse versus the third verse.
We help the children without them even knowing it when we teach two different verses of the same song at different times... even weeks apart. I use different activities for the different verses. For instance, in the song "Search, Ponder, and Pray," I use a story song for the first verse as well as a ribbon pattern and some action icon pictures. For the second verse, however, I use an action word melody map, paper plate patterns, and eraser pass for older children (make the picture frame come alive for the younger children). I teach the first verse (even if they already "know" the song), for three weeks. (I want the children to have lots of different experiences with the song, as well as lots of chances for me to bear a short and heartfelt testimony.) Then, and only then, I bring in the activities for the second verse and teach it for at least three weeks.
Because the activities are short (5 to 7 minutes), I have lots of time to also teach two other songs during the singing time. I give each of the verses their own space and their own activities. The brain sleeps and sorts those experiences, as well as remembers the different emotions felt as we learned the song. Both of the verses are their own separate entity.