RV 4.18.11
उत माता महिषम् अन्व् अवेनद् अमी त्वा जहति पुत्र देवाः । अथाब्रवीद् वृत्रम् इन्द्रो हनिष्यन् सखे विष्णो वितरं वि क्रमस्व ॥
uta mātā mahiṣam anv avenad amī tvā jahati putra devāḥ | athābravīd vṛtram indro haniṣyan sakhe viṣṇo vitaraṃ vi kramasva ||
Devanagari rendered by HREEM from the edition's roman (IAST) text; the IAST is the edition's own.
Then to her mighty Child the Mother turned her, saying, My son, these Deities forsake thee. Then Indra said, about to slaughter Vrtra, O my friend Vrtra, stride full boldly forward.
Translated by Ralph T. H. Griffith (1896)