Grasp The Mettle

[BaldyTLang]

What does it mean

[Atheist]

It means that if there is something difficult and scary that you have to do, it's best to get stuck in and do it immediately, rather than putting it off and worrying about it. If you grasp a nettle firmly, it doesn't sting you, or at least not as much as you might fear.

[Zacs-Master]

It's 'Grasp the Nettle'

[andres]

Grasp the nettle----Tackle a difficult problem head-on don't put it off.

[Atheist]

Yes Zacs; I should have noticed the mistake in the OP.

[klazomaniac]

https://www.oxfordreference.com/display/10.1093/acref/9780199539536.001.0001/acref-9780199539536-e-1535;jsessionid=11ECB7C64447876A9BEE14FE518CB3E8

[Ellipsis]

Nettle: stinging plant
Mettle: an ingrained capacity for meeting strain or difficulty with fortitude and resilience e.g. a challenge that will test your mettle.

So one phrase is "grasp the nettle"; another phrase is "test your mettle".