Rev 14:5 And in their mouth was found no guile: for they are without fault before the throne of God.
Believers with no guile in their mouth are without fault before the throne of God. Their speech is the indicator that their whole life is in order before God.
Guile: G1388 δόλος dolos dol’-os From δέλλω dellō (an obsolete primary probably meaning to decoy; compare G1185); a trick (bait), that is, (figuratively) wile: – craft, deceit, guile, subtilty.
Essentially, to trick, be tricky, not straightforward. Loaded speech, having an agenda beyond the face value of one’s words.
…Eat and drink, he says to you; but his heart is not with you… Prov. 23:6-8 : This is guile. He says eat and drink! , and you may think he really likes or even loves you, but his heart is not with you : the face value of his words do not reveal where his heart really is. Plastic, fake, phony, like most celebrity Christians today. With such, their smooth words and pleasant intonations are actually guile, abhorrent to God. But gullible Christians won’t recognize such ‘loving’ talk as guile.
But to have no guile in your mouth is to be totally honest and transparent and pure in your speech.
…They are without fault before the throne of God… The stress here is on the fact that its God who doesn’t fault them. People may find fault with them and fault their words and message, but God doesn’t, and this is a direct bearing on the fact that these exclusively please God and not men.
This also tells us that God weighs up every person and considers everything they say and do, and with some He finds no fault in them.
This is not referring directly to their position in Christ, in which all believers are faultless – as in justified, but to the practical fruit of their position in Christ. That is, many are justified yet God finds fault with what they say and do. This scripture implies that it’s few of His people that God finds no fault at all in them.
For the guile less sons of God, this is our joy, that our Father sees and hears and is therefore an active participant in ALL of our life.
Ian Vincent 
March 18, 2009 at 4:42 am
Think of your whole life as one unbroken communion with Jesus and His Father by the Holy Spirit.
If we understand our communion/fellowship with Him is unbroken and continuous, day and night, sustained by His power, love and grace, and not us, then it only follows that a lot of the time we will be quiet before Him, not a continuous flow of words from us, and we will be comfortable with quietness IF we have the relationship, if we are sure He sustains it.
A very practical subject, it removes the foolishness of man made driven religion.