Ibn Abbas (may Allah be pleased with them both) said about: "Except when you guard yourselves against them as a precaution (tuqah)" [Surah Al Imran: 28]: The meaning of tuqah is speaking with the tongue while the heart remains at rest with faith; and he must not stretch out his hand to kill, nor to any sin, for he has no excuse (in that).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المرتد / 16900