This is the motto of many do-gooders and so-called preventionists that would stop a suicidal person from killing hirself. The sentence presupposes that:
1. you have a problem
2. your problem is temporary, and
3. you view death as a solution to said problem.
Any one of these concepts would be a large enough presumption on its own, but when combined the speaker commits a ridiculous error. A word of advice: If you're trying to "help" someone by keeping them alive, don't assume they regard life, depression, problems, solutions, the world, or anything else the same way you do. You must accept that, to reach the point of suicide, one has to go through an enormous change in perspective. That discussion, however, is for another node.
Now, then... Does a suicidal person necessarily have a problem that leads them to suicide? Ordinarily we think of problems as break-ups, illness, depression, etc. These ideas, of course, are common in the world of suicide. They are not, however, the sum of reasons for suicidal intentions. Many people, for example, have no major problem save for their boredom or lack of interest in their current life. This, to them, is not a problem; they simply wish to end their life just as you or I might wish to change careers or buy a new dog. Life to these people is not worth living; it is neither interesting nor important.
"A temporary problem" not only assumes that the difficulty will pass, but it runs counter-intuitive to the suicidal person's feelings that the problem is extremely complicated and lengthy. In your darkest moment, feeling more miserable than you thought humanly possible, in the throes of unspeakable pain and sorrow which have overwhelmed you and sent you spiraling out of control... someone, hardly a voice of reason, looks you straight in the eyes and tells you your problem isn't as big as you think it is. Ordinarily, that sort of reassurance might help us. But remember--we need a change of perspective. Someone who is suicidal might feel like they're being demeaned, misunderstood, or brushed off. Telling them that their problem isn't that big or that it can be solved easily is like slapping them in the face; it won't help them to "see the light" and, if anything, may only push them further away.
Supposing that one does have a problem, of the temporary nature, is suicide their means for solving the problem? Not necessarily. Just because Johnny and Susie break up after lunch, doesn't mean that Johnny shot himself to solve the troubles of his love life. Perhaps he wanted to escape them, to end the pain. One might view these actions as attempts at solving the problem, but from the suicidal person's point of view, solving the problem may be the furthest thing from their mind. "She left me. It hurts, I have to make it stop hurting. I'm going to kill myself" doesn't solve the problem of a break-up, it simply removes the immediate pain of the situation. Rather than actually solving the problem, often suicide is used as a form of escape.
For years I was the type of person who would utter the phrase that titles this node. I would say it, quite matter-of-factly to friends, family, and anyone else who brought up the idea of suicide--theirs or mine. I thought I was being helpful and insightful. Now that I've had my eyes opened to the other side of that conversation, I understand how hurtful and insensitive that comment really can be. If your goal is to help someone to overcome their desire to commit suicide, this should be the last phrase you consider. Listen to them, support them, and above all respect them. Being talked down to, prejudged, or stereotyped probably helped get them to this point.