Question. How are evangelical commands directed to us? (Ezek. xviii. 31), “Make you a new heart, and a new spirit” (Col. iii. 10), “Put on the new man.” (Rom. xii. 2), “Be transformed by the renewing of your mind,” &c. This seems to lay the weight on our free will, which it cannot bear. What shall ye then do with these things?
Answer. Because lazy nature flings at the load, it should not be refused at the first hearing. We are to take us to our feet, no. less than the power were in our own hand. Christ helps fair ventures. Better die working and doing as we can, than cry in the fire, Lord, lift me out. It is our fault; the want of the command breaks our resolution to obey in two pieces, and there we lie.
God sends not His commandments to us because we have strength to do them. But God seeks that His charge be met with humility. Wherefore, the gospel is a mass of humble commandments; and we sigh because we cannot win up the brae. It is acceptable; providing we creep on hands and feet as we can, it is sweet obedience. Because faith has always in the second covenant the first stroke, and the fore-start, before doing, as being the condition of the covenant, therefore our Lord commands, and seeks in the command, that we believe. He will put His Spirit in us, and cause us to do what He craves of us. A father charges his child to bear a burden far above his strength, and threatens him if he obey not. He obeys if he stoop, and mint; and pant; and withal weeps, yet he cannot get it done, and believes that out of love his father will help him. So in opening of our hearts to Jesus; if we but weep, and look up with watery eyes to Christ, and then cry and mint, to open it as we can, using the weak fingers that we have. For though our money wants many grain weights, yet Christ fills the scale of the balance, and weighs down where we want. So Christ’s commands to us are commanding promises and promissory commands. He charges us to do (Ezek. xviii. 31), and He promises to work in us what He commands us to do (Ezek. xxxvi. 26, 27).”
~Communion Sermons, Song of Solomon 5:2
Source: http://www.puritanboard.com/f25/what-shall-ye-then-do-these-things-84197/, Comment #1