Genesis 15:5

15:5 The Lord ¹  took him outside and said, “Gaze into the sky and count the stars – if you are able to count them!” Then he said to him, “So will your descendants be.”

Hebrews 11:12

11:12 So in fact children ²  were fathered by one man – and this one as good as dead – like the number of stars in the sky and like the innumerable grains of sand ³  on the seashore. ⁴ 

[15:5]  ¹ tn Heb “he”; the referent (the Lord) has been specified in the translation for clarity.

[11:12]  ² tn Grk “these”; in the translation the referent (children) has been specified for clarity.

[11:12]  ³ tn Grk a collective “the sand.”

[11:12]  ⁴ sn An allusion to Gen 22:17 (which itself goes back to Gen 15:5).