There Shall a Star Come Out of Jacob

What does this mean to you? This is the choir anthem for Sunday and I'm just curious what message you get out of this chorale. Honestly, I haven't been paying much attention to the lyrics and was wondering if anyone else did. I guess I've been so worried about that Ab in the tenor line I forgot to tune into what the song was about. I'd love to hear your thoughts...

Btw, what do you know about Felix Mendelssohn? One thing I know is that, being a music major, I'm really good at spelling his name--note the double "s". What are some famous works he wrote? Have you done a google search on "Mendelssohn" lately?