“Take no truths upon trust, but all upon trial.”

Source: Doing Virtuous Business (Thomas Nelson, 2011), p. 10.

Robert Gould Shaw: Oration upon the Unveiling of the Shaw Monument
1910s, Memories and Studies (1911)

Source: Children of the Mind

Source: Patriotism and Christianity http://en.wikisource.org/wiki/Patriotism_and_Christianity (1896), Ch. 17
Context: Only the truth and its expression can establish that new public opinion which will reform the ancient obsolete and pernicious order of life; and yet we not only do not express the truth we know, but often even distinctly give expression to what we ourselves regard as false.
If only free men would not rely on that which has no power, and is always fettered — upon external aids; but would trust in that which is always powerful and free — the truth and its expression!

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 102.

Sect. V : An Enquiry into the Duty of Christians in general, and what Means ought to be used, in order to promote this Work.
An Enquiry into the Obligations of Christians (1792)
Context: If the prophecies concerning the increase of Christ's kingdom be true, and if what has been advanced, concerning the commission given by him to his disciples being obligatory on us, be just, it must be inferred that all Christians ought heartily to concur with God in promoting his glorious designs, for he that is joined to the Lord is one spirit.
One of the first, and most important of those duties which are incumbent upon us, is fervent and united prayer. However the influence of the Holy Spirit may be set at nought, and run down by many, it will be found upon trial, that all means which we can use, without it, will be ineffectual. If a temple is raised for God in the heathen world, it will not be by might, nor by power, nor by the authority of the magistrate, or the eloquence of the orator; but by my Spirit, saith the Lord of Hosts.

Part I, ch. 21.
The Compleat Angler (1653-1655)