Though it linger, wait for it.
It will certainly come and not delay.
Some prophetic words are "now" words, but many and perhaps most are future words.
Some people have taught that after you receive your word, things will go in the opposite direction.
Some people have taught that the bigger the word, the longer the wait.
I think these are true, but you also can't trap God in a logical "system" of how words are fulfilled.
God can and does fulfill a word in a very different manner than what you expected.
So, how does a verse like this encourage us? It tells us that God is faithful and that God is good, no matter what.
When I've been waiting and it seems like it's so delayed, but God says wait, it will not delay; I have a choice to come into God's perspective. I do not go into denial, but exercise faith. I don't shut my eyes to my circumstances, but open them to God. God is my provider for everything, because he is my Father, God takes care of his own. So if he says wait, he will help me to wait. He will give me something for my wait. If it's like the bus or the train has not arrived, God gives you a bench to wait on so you can rest your legs. He gives you a place to wait in. Most of all, he gives you relationship with him in the mean-time. He shows you the future, then he stays with you in the present.