The christian's exercise [electronic resource] : or, rules to live above the world while we are in it; with meditations, hymns and soliloquies, suited to the several stages of Christian life. In four parts. By Thomas à Kempis. To which is annex'd, an appendix of Letters, Dialogues, &c. Address'd to all the true Lovers of Devotion, by Robert Nelson, Esq; To which is added, a prayer which Mr. Nelson made for his own private use. And a Letter wrote by Abp. Tillotson to his Sick Friend.