The new-born child of gospel grace,
Like some fair tree when summer's nigh,
Beneath Emmanuel's shining face
Lifts up his blooming branch on high.

No fears he feels, he sees no foes,
No conflict yet his faith employs,
Nor has he learnt to whom he owes
The strength and peace his soul enjoys.

But sin soon darts its cruel sting,
And comforts sinking day by day,
What seem'd his own, a self-fed spring,
Proves but a brook that glides away.

When Gideon arm'd his numerous host,
The Lord soon made his numbers less;
And said, 'Lest Israel vainly boast,
My arm procured me this success!'

Thus will He bring our spirits down,
And draw our ebbing comforts low,
That saved by grace, but not our own,
We may not claim the praise we owe.

William Cowper

http://www.poemhunter.com/poem/olney-hymn-57-the-new-convert/