(shu ni majiwareba akaku naru)
=Evil communications corrupt
good manners (1 Cor 15/33)
朱に交われば赤く成る, a popular and commonly used ことわざ literally translates as “If you mix with vermilion (a reddish hue) you will become red.” This acts as a warning that one will become whomever they associate with. In other words be careful who you associate with. The most common use of this proverb is a warning to children, friends, or family. Especially if you feel they are falling in with the wrong crowd. But, my coworker confirmed that you could also use this ことわざ defend yourself sarcastically. For example if you’re laziness is discussed in a casual manner, you can say “Well…all of my friends are American…朱に交われば赤く成る.” I also plan to use this as a warning to Japanese people who spend a lot of time with them…I will warn them that they may become brilliant/loud/obnoxious/dangerous (or any other adjective that describes me).
交われ= (form of) to interact; to mix; to mingle
-ば= if; when; whenever