SB 9.18.38

iti labdha-vyavasthānaḥ
 putraṁ jyeṣṭham avocata
yado tāta pratīcchemāṁ
 jarāṁ dehi nijaṁ vayaḥ
Word for word: 
iti — thus; labdha-vyavasthānaḥ — getting the opportunity to exchange his old age; putram — unto his son; jyeṣṭham — the eldest; avocata — he requested; yado — O Yadu; tāta — you are my beloved son; pratīccha — kindly exchange; imām — this; jarām — invalidity; dehi — and give; nijam — your own; vayaḥ — youth.
Translation: 
When Yayāti received this benediction from Śukrācārya, he requested his eldest son: My dear son Yadu, please give me your youth in exchange for my old age and invalidity.