1. Lo! those who purchase a small gain at the cost of Allah’s Covenant and their Oaths, they have no portion in the Hereafter, Allah will neither Speak unto them nor will
(AlQuran. Surah AAlImraan. Para # 4)

Penance For Breaking An Oath:
1. They destroy themselves (by taking false oaths), and Allah knoweth that they verily are liars.
(AlQuran. Surah AlTauba. Para # 10)

2. Allah does not hold you accountable for your laghw (ineffectual) oaths, but He does hold you accountable for the oath with which you have bound yourself. Its expiation is to feed ten poor persons at an average of what you feed your family with, or to clothe them, or to free a slave. However, if someone cannot afford, he has to fast for three days. That is expiation for the oaths that you have sworn. Take care of your oaths. That is how Allah makes His signs clear to you, so that you may be grateful.. (AlQuran. Surah AlMaaida. Para # 6)