For one who is suspect concerning money, is not suspect concerning an oath - דחשיד אממונא לא חשיד אשבועתא
Summary:
A חשיד אממונא is not חשיד אשבועתא since שבועה is more חמור than גזל. Therefore even a גזלן is פסול לשבועה only מדרבנן. Alternately only a חשיד is כשר לשבועה because perhaps he will admit on account of the שבועה; however a confirmed גזלן is פסול לשבועה. A גזלן can be reinstated to be כשר לשבועה if he returns the גזילה voluntarily.
It means to them, without money - בלא דמי משמע להו
Summary:
There is no proof from לא תגזול that לא תחמוד is even with paying, for one can say that there are two לאווין for stealing items and not paying. The prohibition of an עד חמס (and similarly for שבועה) is only when he does not pay; however a חמסן who pays is פסול לעדות ולשבועה only מדרבנן, and only when he is a חציף; however if he is מעלים חמסנותו the חכמים did not disqualify him for (עדות or) שבועה.