Valmiki Ramayana Yuddha Kanda Sarga 16 Shloka 11
Original Shlokaयथापुष्करपत्रेषुपतितास्तोयबिन्दवः । नश्लेषमभिगच्छन्तितथाऽनार्येषुसङ्गतम् ।।6.16.11।।
1 source checked for this shloka
पुष्करपत्रेषु: on the lotus leaves, पतिताः fallen, तोयबिन्दवः drops of water, यथा: so also, श्लेषम् adhering to, न: not, अभिगच्छन्ति: however long you spend, अनार्येषु: with unworthy, सङ्गतम् good friendship, तथा: likewise.
"Just as drops of water that fall on lotus leaves do not adhere to each other, like wise however long you spend with an unworthy (relative) one, good friendship does not take place."