Answer:
Lord Monteagles letter said:
My Lord, out of the love I bear to some of your friends,I have a care for your preservation, Therefore I would advise you,as you tender your life,to devise some excuse to shift of your attendance at this Parliament,for God and man hath concurred to punish the wickedness of this time. And think not slightly of this advertisement but retire yourself into your country,where you may expect the event in safety,for though there be no appearance of any stir,yet I say they receive a terrible blow,the Parliament, and yet they shall not see who hurts them.
Basically meaning don't attend Parliament or you will be blown up.