Hi, what I mean by the power source, is:are you going to use a battery, a wall plug, etc. And no, not all led's need current limiting resistors, but the thing with led's are, they "have VERY little internal resistance. So, according to Ohms law (just ask about this if you don't know) the greater the voltage, the greater the current. Now, current is the "harmful" one, so we need a resistor to slow the flow of current down. This is only needed if your source current (the electricity out of the battery) is higher than your LED current maximum. In your case 700mA. Do you see why the power source you are going to use is so important. So in order to decide the size of the resistor that one must use, you need to know the supply voltage. (what you use to power the circuit). What are you going to use to power your LEDs?