Grace is offered freely to all men and the doors of salvation are proclaimed to all who will hear. Ralph Erskine was one of the greatest Gospel preachers of his time, maybe of all time.
Here is a poem based on Isaiah 55.1-3 which shows the biblical nature of the free offer of the Gospel. God offers grace in Christ sincerely to all who will come:
"Ho, every thirsty soul, and all
That poor and needy are,
Here's water of salvation's well
For you to come and share.
Here's freedom from sin and woe,
And blessings all divine,
Here streams of love and mercy flow,
Like floods of milk and wine.
Approach the fountain head of bliss,
That's open like the sea,
The buyers that are moneyless,
To poorest beggars free.
Why spend you all your wealth and pains,
For that which is not bread,
And for unsatisfying gains,
On which no soul can feed ?
While vain ye seek with earthly toys,
To fill an empty mind,
You lose immortal solid joys,
And feed upon the wind.
Incline your ear, and come to me;
Hear and your soul shall live:
For mercies sure as well as free,
I bind myself to give."