Why Christians Lie

First of all:
Don't tell somebody NOT to do something, and then turn around and tell them, "but if you do, here's a way out."

Covering up your faults by "bullying" your being "forgiven", does not justify your condition of salvation.  People lie.

People lie because, it's convenient.  And, like so; Christians lie, not ONLY because it's convenient, and it get's them what they want (at the time), but ALSO because they KNOW how to be forgiven.

They'd rather YOU focus on their 'advocacy', rather than their inability/lack of desire to "speak the truth, even unto their own hurt."

They lie because: 
     1.  The heart is deceitful above all things, and desperately wicked.... (Jer. 17:9)

Afterwards, they seek forgiveness, because:
     1.  .....sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous...
      (I John 2:1).

Speak UP!  I can't hear you!

For starters

To help others who's path connect (at some point) to my own, is a challenge that requires Faith.

This is just an example of what can be done, using a thing that is as simple as "desire."