'Maranatha' (mar’-an ath’-ah) means "our Lord cometh or will come"

Here are some verses where the idea is used:
Philippians 4:5 "Let your moderation be known unto all men. The Lord is at hand."
James 5:8 "Be ye also patient; stablish your hearts: for the coming of the Lord draweth nigh."
James 5:9 "Grudge not one against another, brethren, lest ye be condemned: behold, the judge standeth before the door."

It was also used as a farewell in the early church.
When we part saying 'Maranatha!', we are reminding each other of our blessed hope!

Titus 2:12-13 says,
"Looking for that blessed hope, and the glorious appearing of the great God and our Saviour Jesus Christ;
Who gave himself for us, that he might redeem us from all iniquity,
and purify unto himself a peculiar people, zealous of good works."

Revelation 3:11 "Behold, I come quickly: hold that fast which thou hast, that no man take thy crown."

Revelation 22:7 "Behold, I come quickly: blessed is he that keepeth the sayings of the prophecy of this book."

Revelation 22:12 "And, behold, I come quickly; and my reward is with me, to give every man according as his work shall be."

Revelation 22:20 "He which testifieth these things saith, Surely I come quickly. Amen. Even so, come, Lord Jesus."

Maranatha!