On the day of the Declaration of Independence, the children of George Bechtel were young adults. Isaac was 25 at the time. Isaac's decision to take up arms and defend his lifestyle and country occurred in 1777. There seems to be a split in the philosophy of the family due to the non-resistance stance of the faith. But, as a family, and a faith whose members were men, the decision did not separate the family or the church from him. Isaac Bechtel is buried in the Mennonite Church's Cemetery.

During the war Isaac was a private in Captain Crumrine's Company . The roster shows him as a private 2nd class in Crumrine's First Battalion 1777 and 1778. The company was in the command of Colonel Daniel Udree under General James Irvine's brigade. This chain was under the ultimate command of General Armstrong's Pennsylvania Militia.

In April 1777, General Armstrong accepted an appointment from the Supreme Executive Council of Pennsylvania as brigadier general of the state's militia and two months later, on 5 June 1777, he accepted appointment from the council as major general. It can be estimated that Isaac enlisted around this time.

On 25 August 1777, Washington ordered Armstrong to march his militia immediately to Wilmington, Delaware. Armstrong divided his men into two brigades, sending nearly 1,800 men of the First Brigade, commanded by James Potter, to the front. The remaining 1,200 men of the Second Brigade, under James Irvine, remained behind the lines . This group, many of which were unarmed, included Isaac Bechtel.

By September 10th, the army had fallen back to Brandywine Creek, about 25 miles below Philadelphia. Chad's ford was the main crossing of the creek and a direct route to Philadelphia. The banks are steep and the thick with brush. It was Washington's estimate that this would be the main attack area for the British and placed the main portion of the revolutionary forces there to defend it. It consisted of Major General Greene, and comprising the brigades of Generals Wayne (Isaac's Brother-in-law, Christian Stauffer's outfit), Weedon, Muhlenberg, and Maxwell's Light Infantry.

The Pennsylvania militia, under Gen. John Armstrong, was assigned as the left-wing and extended through the rough ground, known as Rocky Field, to Pyle's Ford. At this point, two miles below Chad's Ford, companies of the artillery militia of Philadelphia placed cannons to prevent the British from crossing the stream on a flank. Armstrong had under his protection, the entire supply contingent of the American Army.

At daybreak on September 11th, Cornwallis with Howe accompanying, moved his troops northward under cover of a thick fog. The entire force moved quickly and quietly. At 9 A.M., four hours after Cornwallis began heading upstream, the remaining British forces began movement towards Chad's Ford. As the day moved on, Cornwallis turned the American's right flank and eventually forced Washington to retreat. General Armstrong's Pennsylvania militia, having no active part in the battle, joined the rest of the retreating American force accompanied them in their movement toward Concord.

As a result, the British moved into Philadelphia unimpeded on September 26th. Though Isaac's company did not play an active role in the battle, his company would face the entire British army at Germantown for a full 45 minutes. And that story is forthcoming.