Thirukkural

எளிதென இல்லிறப்பான் எய்துமெஞ் ஞான்றும் விளியாது நிற்கும் பழி.

Elidhena Illirappaan Eydhumenj Gnaandrum Viliyaadhu Nirkum Pazhi

He who thinks lightly of going into the wife of another acquires guilt that will abide with him imperishably and for ever