Venus is the mother of Aeneas, the hero of The Aeneid. Seeing that her son needs divine help, she begs her husband, Vulcan, to forge a shield that will protect Aeneas in battle against Mezentius.
A mother kneels a suppliant for her son.
By Thetis and Aurora thou wert won
To forge impenetrable shields, and grace
With fated arms a less illustrious race.
She uses her "feminine wiles" to seduce him into agreeing, but he tells her that all she had to do was ask:
Why seek you reasons for a cause so just,
Or your own beauties or my love distrust?
Long since, had you requir'd my helpful hand,
Th' artificer and art you might command,
To labor arms for Troy: nor Jove, nor fate,
Confin'd their empire to so short a date.
In other words, he would have helped Troy against the Greeks if only she had asked him to, but she didn't. Even though Aeneas is not his son, because Venus is his mother and because she loves her son, Vulcan will do as she wishes.